diff --git a/84 Super Star Trek/csharp/Game.cs b/84 Super Star Trek/csharp/Game.cs
index f2e1c819..96261498 100644
--- a/84 Super Star Trek/csharp/Game.cs	
+++ b/84 Super Star Trek/csharp/Game.cs	
@@ -4,7 +4,6 @@ using SuperStarTrek.Resources;
 using SuperStarTrek.Space;
 using SuperStarTrek.Systems;
 using SuperStarTrek.Systems.ComputerFunctions;
-using static System.StringComparison;
 
 namespace SuperStarTrek
 {
@@ -22,17 +21,17 @@ namespace SuperStarTrek
         private int _initialKlingonCount;
         private Enterprise _enterprise;
 
-        public Game()
+        internal Game(Output output, Input input, Random random)
         {
-            _output = new Output();
-            _input = new Input(_output);
-            _random = new Random();
+            _output = output;
+            _input = input;
+            _random = random;
         }
 
-        public float Stardate => _currentStardate;
-        public float StardatesRemaining => _finalStarDate - _currentStardate;
+        internal float Stardate => _currentStardate;
+        internal float StardatesRemaining => _finalStarDate - _currentStardate;
 
-        public void DoIntroduction()
+        internal void DoIntroduction()
         {
             _output.Write(Strings.Title);
 
@@ -44,11 +43,10 @@ namespace SuperStarTrek
             }
         }
 
-        public void Play()
+        internal void Play()
         {
             Initialise();
             var gameOver = false;
-            var newQuadrantText = Strings.StartText;
 
             while (!gameOver)
             {
@@ -120,7 +118,7 @@ namespace SuperStarTrek
         private Quadrant BuildCurrentQuadrant() =>
            new Quadrant(_galaxy[_currentQuadrant], _enterprise, _random, _galaxy, _input, _output);
 
-        public bool Replay() => _galaxy.StarbaseCount > 0 && _input.GetString(Strings.ReplayPrompt, "Aye");
+        internal bool Replay() => _galaxy.StarbaseCount > 0 && _input.GetString(Strings.ReplayPrompt, "Aye");
 
         private bool CheckIfStranded()
         {
diff --git a/84 Super Star Trek/csharp/Input.cs b/84 Super Star Trek/csharp/Input.cs
index 3011738b..2b37b2ba 100644
--- a/84 Super Star Trek/csharp/Input.cs	
+++ b/84 Super Star Trek/csharp/Input.cs	
@@ -10,24 +10,24 @@ namespace SuperStarTrek
     {
         private readonly Output _output;
 
-        public Input(Output output)
+        internal Input(Output output)
         {
             _output = output;
         }
 
-        public void WaitForAnyKeyButEnter(string prompt)
+        internal void WaitForAnyKeyButEnter(string prompt)
         {
             _output.Write($"Hit any key but Enter {prompt} ");
             while (Console.ReadKey(intercept: true).Key == ConsoleKey.Enter);
         }
 
-        public string GetString(string prompt)
+        internal string GetString(string prompt)
         {
             _output.Prompt(prompt);
             return Console.ReadLine();
         }
 
-        public float GetNumber(string prompt)
+        internal float GetNumber(string prompt)
         {
             _output.Prompt(prompt);
 
@@ -44,24 +44,24 @@ namespace SuperStarTrek
             }
         }
 
-        public (float X, float Y) GetCoordinates(string prompt)
+        internal (float X, float Y) GetCoordinates(string prompt)
         {
             _output.Prompt($"{prompt} (X,Y)");
             var responses = ReadNumbers(2);
             return (responses[0], responses[1]);
         }
 
-        public bool TryGetNumber(string prompt, float minValue, float maxValue, out float value)
+        internal bool TryGetNumber(string prompt, float minValue, float maxValue, out float value)
         {
             value = GetNumber($"{prompt} ({minValue}-{maxValue})");
 
             return value >= minValue && value <= maxValue;
         }
 
-        internal bool GetString(string replayPrompt, string trueValue)
-            => GetString(replayPrompt).Equals(trueValue, InvariantCultureIgnoreCase);
+        internal bool GetString(string replayPrompt, string trueValue) =>
+            GetString(replayPrompt).Equals(trueValue, InvariantCultureIgnoreCase);
 
-        public Command GetCommand()
+        internal Command GetCommand()
         {
             while(true)
             {
@@ -82,7 +82,7 @@ namespace SuperStarTrek
             }
         }
 
-        public bool TryGetCourse(string prompt, string officer, out Course course)
+        internal bool TryGetCourse(string prompt, string officer, out Course course)
         {
             if (!TryGetNumber(prompt, 1, 9, out var direction))
             {
@@ -95,7 +95,7 @@ namespace SuperStarTrek
             return true;
         }
 
-        public bool GetYesNo(string prompt, YesNoMode mode)
+        internal bool GetYesNo(string prompt, YesNoMode mode)
         {
             _output.Prompt($"{prompt} (Y/N)");
             var response = Console.ReadLine().ToUpperInvariant();
@@ -150,7 +150,7 @@ namespace SuperStarTrek
             return numbers;
         }
 
-        public enum YesNoMode
+        internal enum YesNoMode
         {
             TrueOnY,
             FalseOnN
diff --git a/84 Super Star Trek/csharp/Objects/Enterprise.cs b/84 Super Star Trek/csharp/Objects/Enterprise.cs
index 4adf81df..2f587631 100644
--- a/84 Super Star Trek/csharp/Objects/Enterprise.cs	
+++ b/84 Super Star Trek/csharp/Objects/Enterprise.cs	
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 using SuperStarTrek.Commands;
 using SuperStarTrek.Resources;
 using SuperStarTrek.Space;
@@ -31,22 +30,33 @@ namespace SuperStarTrek.Objects
             _input = input;
         }
 
-        public Quadrant Quadrant => _quadrant;
-        public Coordinates QuadrantCoordinates => _quadrant.Coordinates;
-        public Coordinates SectorCoordinates { get; private set; }
+        internal Quadrant Quadrant => _quadrant;
 
-        public string Condition => GetCondition();
-        public LibraryComputer Computer => (LibraryComputer)_commandExecutors[Command.COM];
-        public ShieldControl ShieldControl => (ShieldControl)_commandExecutors[Command.SHE];
-        public float Energy => TotalEnergy - ShieldControl.ShieldEnergy;
-        public float TotalEnergy { get; private set; }
-        public int DamagedSystemCount => _systems.Count(s => s.IsDamaged);
-        public IEnumerable<Subsystem> Systems => _systems;
-        public PhotonTubes PhotonTubes => (PhotonTubes)_commandExecutors[Command.TOR];
-        public bool IsDocked => _quadrant.EnterpriseIsNextToStarbase;
-        public bool IsStranded => TotalEnergy < 10 || Energy < 10 && ShieldControl.IsDamaged;
+        internal Coordinates QuadrantCoordinates => _quadrant.Coordinates;
 
-        public Enterprise Add(Subsystem system)
+        internal Coordinates SectorCoordinates { get; private set; }
+
+        internal string Condition => GetCondition();
+
+        internal LibraryComputer Computer => (LibraryComputer)_commandExecutors[Command.COM];
+
+        internal ShieldControl ShieldControl => (ShieldControl)_commandExecutors[Command.SHE];
+
+        internal float Energy => TotalEnergy - ShieldControl.ShieldEnergy;
+
+        internal float TotalEnergy { get; private set; }
+
+        internal int DamagedSystemCount => _systems.Count(s => s.IsDamaged);
+
+        internal IEnumerable<Subsystem> Systems => _systems;
+
+        internal PhotonTubes PhotonTubes => (PhotonTubes)_commandExecutors[Command.TOR];
+
+        internal bool IsDocked => _quadrant.EnterpriseIsNextToStarbase;
+
+        internal bool IsStranded => TotalEnergy < 10 || Energy < 10 && ShieldControl.IsDamaged;
+
+        internal Enterprise Add(Subsystem system)
         {
             _systems.Add(system);
             _commandExecutors[system.Command] = system;
@@ -54,7 +64,7 @@ namespace SuperStarTrek.Objects
             return this;
         }
 
-        public void StartIn(Quadrant quadrant)
+        internal void StartIn(Quadrant quadrant)
         {
             _quadrant = quadrant;
             quadrant.Display(Strings.StartText);
@@ -68,24 +78,14 @@ namespace SuperStarTrek.Objects
                 _ => "Green"
             };
 
-        public CommandResult Execute(Command command)
+        internal CommandResult Execute(Command command)
         {
             if (command == Command.XXX) { return CommandResult.GameOver; }
 
             return _commandExecutors[command].ExecuteCommand(_quadrant);
         }
 
-        public void Refuel() => TotalEnergy = _maxEnergy;
-
-        internal bool Recognises(string command)
-        {
-            throw new NotImplementedException();
-        }
-
-        internal string GetCommandList()
-        {
-            throw new NotImplementedException();
-        }
+        internal void Refuel() => TotalEnergy = _maxEnergy;
 
         public override string ToString() => "<*>";
 
diff --git a/84 Super Star Trek/csharp/Objects/Klingon.cs b/84 Super Star Trek/csharp/Objects/Klingon.cs
index 4e277b07..78c307e5 100644
--- a/84 Super Star Trek/csharp/Objects/Klingon.cs	
+++ b/84 Super Star Trek/csharp/Objects/Klingon.cs	
@@ -7,19 +7,19 @@ namespace SuperStarTrek.Objects
     {
         private readonly Random _random;
 
-        public Klingon(Coordinates sector, Random random)
+        internal Klingon(Coordinates sector, Random random)
         {
             Sector = sector;
             _random = random;
             Energy = _random.GetFloat(100, 300);
         }
 
-        public float Energy { get; private set; }
-        public Coordinates Sector { get; private set; }
+        internal float Energy { get; private set; }
+        internal Coordinates Sector { get; private set; }
 
         public override string ToString() => "+K+";
 
-        public CommandResult FireOn(Enterprise enterprise)
+        internal CommandResult FireOn(Enterprise enterprise)
         {
             var attackStrength = _random.GetFloat();
             var distanceToEnterprise = Sector.GetDistanceTo(enterprise.SectorCoordinates);
diff --git a/84 Super Star Trek/csharp/Objects/Starbase.cs b/84 Super Star Trek/csharp/Objects/Starbase.cs
index 4befa73a..1ef4a85e 100644
--- a/84 Super Star Trek/csharp/Objects/Starbase.cs	
+++ b/84 Super Star Trek/csharp/Objects/Starbase.cs	
@@ -9,7 +9,7 @@ namespace SuperStarTrek.Objects
         private readonly Output _output;
         private readonly float _repairDelay;
 
-        public Starbase(Coordinates sector, Random random, Input input, Output output)
+        internal Starbase(Coordinates sector, Random random, Input input, Output output)
         {
             Sector = sector;
             _repairDelay = random.GetFloat() * 0.5f;
diff --git a/84 Super Star Trek/csharp/Output.cs b/84 Super Star Trek/csharp/Output.cs
index ed960eea..6a377bce 100644
--- a/84 Super Star Trek/csharp/Output.cs	
+++ b/84 Super Star Trek/csharp/Output.cs	
@@ -4,33 +4,33 @@ namespace SuperStarTrek
 {
     internal class Output
     {
-        public Output Write(string text)
+        internal Output Write(string text)
         {
             Console.Write(text);
             return this;
         }
 
-        public Output Write(string format, params object[] args)
+        internal Output Write(string format, params object[] args)
         {
             Console.Write(format, args);
             return this;
         }
 
-        public Output WriteLine(string text = "")
+        internal Output WriteLine(string text = "")
         {
             Console.WriteLine(text);
             return this;
         }
 
 
-        public Output NextLine()
+        internal Output NextLine()
         {
             Console.WriteLine();
             return this;
         }
 
 
-        public Output Prompt(string text = "")
+        internal Output Prompt(string text = "")
         {
             Console.Write($"{text}? ");
             return this;
diff --git a/84 Super Star Trek/csharp/Program.cs b/84 Super Star Trek/csharp/Program.cs
index 7f8395a6..7080df29 100644
--- a/84 Super Star Trek/csharp/Program.cs	
+++ b/84 Super Star Trek/csharp/Program.cs	
@@ -29,8 +29,11 @@ namespace SuperStarTrek
     {
         static void Main()
         {
-            var foo = Utils.DirectionAndDistance.From(1,1).To(4,5);
-            var game = new Game();
+            var output = new Output();
+            var input = new Input(output);
+            var random = new Random();
+
+            var game = new Game(output, input, random);
 
             game.DoIntroduction();
 
diff --git a/84 Super Star Trek/csharp/Random.cs b/84 Super Star Trek/csharp/Random.cs
index 5ed47805..ae51d95b 100644
--- a/84 Super Star Trek/csharp/Random.cs	
+++ b/84 Super Star Trek/csharp/Random.cs	
@@ -6,20 +6,20 @@ namespace SuperStarTrek
     {
         private static readonly System.Random _random = new();
 
-        public Coordinates GetCoordinate() => new Coordinates(Get1To8Inclusive() - 1, Get1To8Inclusive() - 1);
+        internal Coordinates GetCoordinate() => new Coordinates(Get1To8Inclusive() - 1, Get1To8Inclusive() - 1);
 
         // Duplicates the algorithm used in the original code to get an integer value from 1 to 8, inclusive:
         //     475 DEF FNR(R)=INT(RND(R)*7.98+1.01)
         // Returns a value from 1 to 8, inclusive.
         // Note there's a slight bias away from the extreme values, 1 and 8.
-        public int Get1To8Inclusive() => (int)(GetFloat() * 7.98 + 1.01);
+        internal int Get1To8Inclusive() => (int)(GetFloat() * 7.98 + 1.01);
 
-        public int GetInt(int inclusiveMinValue, int exclusiveMaxValue) =>
+        internal int GetInt(int inclusiveMinValue, int exclusiveMaxValue) =>
             _random.Next(inclusiveMinValue, exclusiveMaxValue);
 
-        public float GetFloat() => (float)_random.NextDouble();
+        internal float GetFloat() => (float)_random.NextDouble();
 
-        public float GetFloat(float inclusiveMinValue, float exclusiveMaxValue)
+        internal float GetFloat(float inclusiveMinValue, float exclusiveMaxValue)
             => GetFloat() * (exclusiveMaxValue - inclusiveMinValue) + inclusiveMinValue;
     }
 }
diff --git a/84 Super Star Trek/csharp/Resources/Strings.cs b/84 Super Star Trek/csharp/Resources/Strings.cs
index ddb768ca..fea41521 100644
--- a/84 Super Star Trek/csharp/Resources/Strings.cs	
+++ b/84 Super Star Trek/csharp/Resources/Strings.cs	
@@ -6,31 +6,31 @@ namespace SuperStarTrek.Resources
 {
     internal static class Strings
     {
-        public static string CombatArea => GetResource();
-        public static string ComputerFunctions => GetResource();
-        public static string Congratulations => GetResource();
-        public static string CourtMartial => GetResource();
-        public static string Destroyed => GetResource();
-        public static string EndOfMission => GetResource();
-        public static string Enterprise => GetResource();
-        public static string Instructions => GetResource();
-        public static string LowShields => GetResource();
-        public static string NoEnemyShips => GetResource();
-        public static string NoStarbase => GetResource();
-        public static string NowEntering => GetResource();
-        public static string Orders => GetResource();
-        public static string PermissionDenied => GetResource();
-        public static string Protected => GetResource();
-        public static string RegionNames => GetResource();
-        public static string RelievedOfCommand => GetResource();
-        public static string RepairEstimate => GetResource();
-        public static string RepairPrompt => GetResource();
-        public static string ReplayPrompt => GetResource();
-        public static string ShieldsDropped => GetResource();
-        public static string ShortRangeSensorsOut => GetResource();
-        public static string StartText => GetResource();
-        public static string Stranded => GetResource();
-        public static string Title => GetResource();
+        internal static string CombatArea => GetResource();
+        internal static string ComputerFunctions => GetResource();
+        internal static string Congratulations => GetResource();
+        internal static string CourtMartial => GetResource();
+        internal static string Destroyed => GetResource();
+        internal static string EndOfMission => GetResource();
+        internal static string Enterprise => GetResource();
+        internal static string Instructions => GetResource();
+        internal static string LowShields => GetResource();
+        internal static string NoEnemyShips => GetResource();
+        internal static string NoStarbase => GetResource();
+        internal static string NowEntering => GetResource();
+        internal static string Orders => GetResource();
+        internal static string PermissionDenied => GetResource();
+        internal static string Protected => GetResource();
+        internal static string RegionNames => GetResource();
+        internal static string RelievedOfCommand => GetResource();
+        internal static string RepairEstimate => GetResource();
+        internal static string RepairPrompt => GetResource();
+        internal static string ReplayPrompt => GetResource();
+        internal static string ShieldsDropped => GetResource();
+        internal static string ShortRangeSensorsOut => GetResource();
+        internal static string StartText => GetResource();
+        internal static string Stranded => GetResource();
+        internal static string Title => GetResource();
 
         private static string GetResource([CallerMemberName] string name = "")
         {
diff --git a/84 Super Star Trek/csharp/Space/Coordinates.cs b/84 Super Star Trek/csharp/Space/Coordinates.cs
index 1619d387..4c4f7b69 100644
--- a/84 Super Star Trek/csharp/Space/Coordinates.cs	
+++ b/84 Super Star Trek/csharp/Space/Coordinates.cs	
@@ -7,7 +7,7 @@ namespace SuperStarTrek.Space
     // Note that the origin is top-left, x increase downwards, and y increases to the right.
     internal record Coordinates
     {
-        public Coordinates(int x, int y)
+        internal Coordinates(int x, int y)
         {
             X = Validated(x, nameof(x));
             Y = Validated(y, nameof(y));
@@ -16,10 +16,10 @@ namespace SuperStarTrek.Space
             SubRegionIndex = Y % 4;
         }
 
-        public int X { get; }
-        public int Y { get; }
-        public int RegionIndex { get; }
-        public int SubRegionIndex { get; }
+        internal int X { get; }
+        internal int Y { get; }
+        internal int RegionIndex { get; }
+        internal int SubRegionIndex { get; }
 
         private int Validated(int value, string argumentName)
         {
diff --git a/84 Super Star Trek/csharp/Space/Galaxy.cs b/84 Super Star Trek/csharp/Space/Galaxy.cs
index 63838567..8fce8fb9 100644
--- a/84 Super Star Trek/csharp/Space/Galaxy.cs	
+++ b/84 Super Star Trek/csharp/Space/Galaxy.cs	
@@ -1,7 +1,5 @@
-using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
-using SuperStarTrek.Objects;
 using SuperStarTrek.Resources;
 
 using static System.StringSplitOptions;
@@ -21,7 +19,7 @@ namespace SuperStarTrek.Space
             _subRegionIdentifiers = new[] { "I", "II", "III", "IV" };
         }
 
-        public Galaxy(Random random)
+        internal Galaxy(Random random)
         {
             _random = random;
 
@@ -46,16 +44,16 @@ namespace SuperStarTrek.Space
             }
         }
 
-        public QuadrantInfo this[Coordinates coordinate] => _quadrants[coordinate.X][coordinate.Y];
+        internal QuadrantInfo this[Coordinates coordinate] => _quadrants[coordinate.X][coordinate.Y];
 
-        public int KlingonCount => _quadrants.SelectMany(q => q).Sum(q => q.KlingonCount);
-        public int StarbaseCount => _quadrants.SelectMany(q => q).Count(q => q.HasStarbase);
-        public IEnumerable<IEnumerable<QuadrantInfo>> Quadrants => _quadrants;
+        internal int KlingonCount => _quadrants.SelectMany(q => q).Sum(q => q.KlingonCount);
+        internal int StarbaseCount => _quadrants.SelectMany(q => q).Count(q => q.HasStarbase);
+        internal IEnumerable<IEnumerable<QuadrantInfo>> Quadrants => _quadrants;
 
         private static string GetQuadrantName(Coordinates coordinates) =>
             $"{_regionNames[coordinates.RegionIndex]} {_subRegionIdentifiers[coordinates.SubRegionIndex]}";
 
-        public IEnumerable<IEnumerable<QuadrantInfo>> GetNeighborhood(Quadrant quadrant) =>
+        internal IEnumerable<IEnumerable<QuadrantInfo>> GetNeighborhood(Quadrant quadrant) =>
             Enumerable.Range(-1, 3)
                 .Select(dx => dx + quadrant.Coordinates.X)
                 .Select(x => GetNeighborhoodRow(quadrant, x));
diff --git a/84 Super Star Trek/csharp/Space/Quadrant.cs b/84 Super Star Trek/csharp/Space/Quadrant.cs
index b333cb7e..0ed2a567 100644
--- a/84 Super Star Trek/csharp/Space/Quadrant.cs	
+++ b/84 Super Star Trek/csharp/Space/Quadrant.cs	
@@ -16,7 +16,7 @@ namespace SuperStarTrek.Space
         private readonly Output _output;
         private bool _displayed = false;
 
-        public Quadrant(
+        internal Quadrant(
             QuadrantInfo info,
             Enterprise enterprise,
             Random random,
@@ -39,13 +39,13 @@ namespace SuperStarTrek.Space
             PositionObject(_ => new Star(), _info.StarCount);
         }
 
-        public Coordinates Coordinates => _info.Coordinates;
-        public bool HasKlingons => _info.KlingonCount > 0;
-        public int KlingonCount => _info.KlingonCount;
-        public bool HasStarbase => _info.HasStarbase;
-        public Starbase Starbase { get; }
+        internal Coordinates Coordinates => _info.Coordinates;
+        internal bool HasKlingons => _info.KlingonCount > 0;
+        internal int KlingonCount => _info.KlingonCount;
+        internal bool HasStarbase => _info.HasStarbase;
+        internal Starbase Starbase { get; }
         internal Galaxy Galaxy { get; }
-        public bool EnterpriseIsNextToStarbase =>
+        internal bool EnterpriseIsNextToStarbase =>
             _info.HasStarbase &&
             Math.Abs(_enterprise.SectorCoordinates.X - Starbase.Sector.X) <= 1 &&
             Math.Abs(_enterprise.SectorCoordinates.Y - Starbase.Sector.Y) <= 1;
@@ -166,10 +166,10 @@ namespace SuperStarTrek.Space
             }
         }
 
-        public IEnumerable<string> GetDisplayLines() => Enumerable.Range(0, 8).Select(x => GetDisplayLine(x));
+        internal IEnumerable<string> GetDisplayLines() => Enumerable.Range(0, 8).Select(x => GetDisplayLine(x));
 
-        private string GetDisplayLine(int x)
-            => string.Join(
+        private string GetDisplayLine(int x) =>
+            string.Join(
                 " ",
                 Enumerable
                     .Range(0, 8)
diff --git a/84 Super Star Trek/csharp/Space/QuadrantInfo.cs b/84 Super Star Trek/csharp/Space/QuadrantInfo.cs
index 70447250..e37a1a9c 100644
--- a/84 Super Star Trek/csharp/Space/QuadrantInfo.cs	
+++ b/84 Super Star Trek/csharp/Space/QuadrantInfo.cs	
@@ -1,5 +1,3 @@
-using SuperStarTrek.Objects;
-
 namespace SuperStarTrek.Space
 {
     internal class QuadrantInfo
@@ -15,13 +13,13 @@ namespace SuperStarTrek.Space
             HasStarbase = hasStarbase;
         }
 
-        public Coordinates Coordinates { get; }
-        public string Name { get; }
-        public int KlingonCount { get; private set; }
-        public bool HasStarbase { get; private set; }
-        public int StarCount { get; }
+        internal Coordinates Coordinates { get; }
+        internal string Name { get; }
+        internal int KlingonCount { get; private set; }
+        internal bool HasStarbase { get; private set; }
+        internal int StarCount { get; }
 
-        public static QuadrantInfo Create(Coordinates coordinates, string name)
+        internal static QuadrantInfo Create(Coordinates coordinates, string name)
         {
             var random = new Random();
             var klingonCount = random.GetFloat() switch
diff --git a/84 Super Star Trek/csharp/Systems/ComputerFunctions/DirectionDistanceCalculator.cs b/84 Super Star Trek/csharp/Systems/ComputerFunctions/DirectionDistanceCalculator.cs
index ff6239ed..f59865a0 100644
--- a/84 Super Star Trek/csharp/Systems/ComputerFunctions/DirectionDistanceCalculator.cs	
+++ b/84 Super Star Trek/csharp/Systems/ComputerFunctions/DirectionDistanceCalculator.cs	
@@ -1,6 +1,3 @@
-using System;
-using System.Collections.Generic;
-using System.Linq;
 using SuperStarTrek.Objects;
 using SuperStarTrek.Space;
 
@@ -11,7 +8,7 @@ namespace SuperStarTrek.Systems.ComputerFunctions
         private readonly Enterprise _enterprise;
         private readonly Input _input;
 
-        public DirectionDistanceCalculator(Enterprise enterprise, Output output, Input input)
+        internal DirectionDistanceCalculator(Enterprise enterprise, Output output, Input input)
             : base("Starbase nav data", output)
         {
             _enterprise = enterprise;
diff --git a/84 Super Star Trek/csharp/Systems/ComputerFunctions/GalacticReport.cs b/84 Super Star Trek/csharp/Systems/ComputerFunctions/GalacticReport.cs
index 8b26cc2e..8be29baf 100644
--- a/84 Super Star Trek/csharp/Systems/ComputerFunctions/GalacticReport.cs	
+++ b/84 Super Star Trek/csharp/Systems/ComputerFunctions/GalacticReport.cs	
@@ -6,7 +6,7 @@ namespace SuperStarTrek.Systems.ComputerFunctions
 {
     internal abstract class GalacticReport : ComputerFunction
     {
-        public GalacticReport(string description, Output output, Galaxy galaxy)
+        internal GalacticReport(string description, Output output, Galaxy galaxy)
             : base(description, output)
         {
             Galaxy = galaxy;
diff --git a/84 Super Star Trek/csharp/Systems/ComputerFunctions/StarbaseDataCalculator.cs b/84 Super Star Trek/csharp/Systems/ComputerFunctions/StarbaseDataCalculator.cs
index 0d2c5b50..7a87f970 100644
--- a/84 Super Star Trek/csharp/Systems/ComputerFunctions/StarbaseDataCalculator.cs	
+++ b/84 Super Star Trek/csharp/Systems/ComputerFunctions/StarbaseDataCalculator.cs	
@@ -8,7 +8,7 @@ namespace SuperStarTrek.Systems.ComputerFunctions
     {
         private readonly Enterprise _enterprise;
 
-        public StarbaseDataCalculator(Enterprise enterprise, Output output)
+        internal StarbaseDataCalculator(Enterprise enterprise, Output output)
             : base("Starbase nav data", output)
         {
             _enterprise = enterprise;
diff --git a/84 Super Star Trek/csharp/Systems/ComputerFunctions/StatusReport.cs b/84 Super Star Trek/csharp/Systems/ComputerFunctions/StatusReport.cs
index f80ba7bb..26a299a8 100644
--- a/84 Super Star Trek/csharp/Systems/ComputerFunctions/StatusReport.cs	
+++ b/84 Super Star Trek/csharp/Systems/ComputerFunctions/StatusReport.cs	
@@ -10,7 +10,7 @@ namespace SuperStarTrek.Systems.ComputerFunctions
         private readonly Galaxy _galaxy;
         private readonly Enterprise _enterprise;
 
-        public StatusReport(Game game, Galaxy galaxy, Enterprise enterprise, Output output)
+        internal StatusReport(Game game, Galaxy galaxy, Enterprise enterprise, Output output)
             : base("Status report", output)
         {
             _game = game;
diff --git a/84 Super Star Trek/csharp/Systems/ComputerFunctions/TorpedoDataCalculator.cs b/84 Super Star Trek/csharp/Systems/ComputerFunctions/TorpedoDataCalculator.cs
index 09c71859..ec837fc4 100644
--- a/84 Super Star Trek/csharp/Systems/ComputerFunctions/TorpedoDataCalculator.cs	
+++ b/84 Super Star Trek/csharp/Systems/ComputerFunctions/TorpedoDataCalculator.cs	
@@ -8,7 +8,7 @@ namespace SuperStarTrek.Systems.ComputerFunctions
     {
         private readonly Enterprise _enterprise;
 
-        public TorpedoDataCalculator(Enterprise enterprise, Output output)
+        internal TorpedoDataCalculator(Enterprise enterprise, Output output)
             : base("Photon torpedo data", output)
         {
             _enterprise = enterprise;
diff --git a/84 Super Star Trek/csharp/Systems/DamageControl.cs b/84 Super Star Trek/csharp/Systems/DamageControl.cs
index 6ce41bbe..8fbf21d3 100644
--- a/84 Super Star Trek/csharp/Systems/DamageControl.cs	
+++ b/84 Super Star Trek/csharp/Systems/DamageControl.cs	
@@ -9,7 +9,7 @@ namespace SuperStarTrek.Systems
         private readonly Enterprise _enterprise;
         private readonly Output _output;
 
-        public DamageControl(Enterprise enterprise, Output output)
+        internal DamageControl(Enterprise enterprise, Output output)
             : base("Damage Control", Command.DAM, output)
         {
             _enterprise = enterprise;
@@ -40,7 +40,7 @@ namespace SuperStarTrek.Systems
             return CommandResult.Ok;
         }
 
-        public void WriteDamageReport()
+        internal void WriteDamageReport()
         {
             _output.NextLine().WriteLine("Device             State of Repair");
             foreach (var system in _enterprise.Systems)
diff --git a/84 Super Star Trek/csharp/Systems/LibraryComputer.cs b/84 Super Star Trek/csharp/Systems/LibraryComputer.cs
index b2e47d2a..df5c6868 100644
--- a/84 Super Star Trek/csharp/Systems/LibraryComputer.cs	
+++ b/84 Super Star Trek/csharp/Systems/LibraryComputer.cs	
@@ -10,7 +10,7 @@ namespace SuperStarTrek.Systems
         private readonly Input _input;
         private readonly ComputerFunction[] _functions;
 
-        public LibraryComputer(Output output, Input input, params ComputerFunction[] functions)
+        internal LibraryComputer(Output output, Input input, params ComputerFunction[] functions)
             : base("Library-Computer", Command.COM, output)
         {
             _output = output;
diff --git a/84 Super Star Trek/csharp/Systems/LongRangeSensors.cs b/84 Super Star Trek/csharp/Systems/LongRangeSensors.cs
index 84ed7a87..a873eeba 100644
--- a/84 Super Star Trek/csharp/Systems/LongRangeSensors.cs	
+++ b/84 Super Star Trek/csharp/Systems/LongRangeSensors.cs	
@@ -1,10 +1,5 @@
-
-using System;
-using System.Collections.Generic;
 using System.Linq;
 using SuperStarTrek.Commands;
-using SuperStarTrek.Objects;
-using SuperStarTrek.Resources;
 using SuperStarTrek.Space;
 
 namespace SuperStarTrek.Systems
@@ -14,7 +9,7 @@ namespace SuperStarTrek.Systems
         private readonly Galaxy _galaxy;
         private readonly Output _output;
 
-        public LongRangeSensors(Galaxy galaxy, Output output)
+        internal LongRangeSensors(Galaxy galaxy, Output output)
             : base("Long Range Sensors", Command.LRS, output)
         {
             _galaxy = galaxy;
diff --git a/84 Super Star Trek/csharp/Systems/PhaserControl.cs b/84 Super Star Trek/csharp/Systems/PhaserControl.cs
index 18566294..9207ad94 100644
--- a/84 Super Star Trek/csharp/Systems/PhaserControl.cs	
+++ b/84 Super Star Trek/csharp/Systems/PhaserControl.cs	
@@ -13,7 +13,7 @@ namespace SuperStarTrek.Systems
         private readonly Input _input;
         private readonly Random _random;
 
-        public PhaserControl(Enterprise enterprise, Output output, Input input, Random random)
+        internal PhaserControl(Enterprise enterprise, Output output, Input input, Random random)
             : base("Phaser Control", Command.PHA, output)
         {
             _enterprise = enterprise;
diff --git a/84 Super Star Trek/csharp/Systems/PhotonTubes.cs b/84 Super Star Trek/csharp/Systems/PhotonTubes.cs
index a807d16c..37613037 100644
--- a/84 Super Star Trek/csharp/Systems/PhotonTubes.cs	
+++ b/84 Super Star Trek/csharp/Systems/PhotonTubes.cs	
@@ -11,7 +11,7 @@ namespace SuperStarTrek.Systems
         private readonly Output _output;
         private readonly Input _input;
 
-        public PhotonTubes(int tubeCount, Enterprise enterprise, Output output, Input input)
+        internal PhotonTubes(int tubeCount, Enterprise enterprise, Output output, Input input)
             : base("Photon Tubes", Command.TOR, output)
         {
             TorpedoCount = _tubeCount = tubeCount;
@@ -20,7 +20,7 @@ namespace SuperStarTrek.Systems
             _input = input;
         }
 
-        public int TorpedoCount { get; private set; }
+        internal int TorpedoCount { get; private set; }
 
         protected override bool CanExecuteCommand() => HasTorpedoes() && IsOperational("{name} are not operational");
 
diff --git a/84 Super Star Trek/csharp/Systems/ShieldControl.cs b/84 Super Star Trek/csharp/Systems/ShieldControl.cs
index a7518359..df42c125 100644
--- a/84 Super Star Trek/csharp/Systems/ShieldControl.cs	
+++ b/84 Super Star Trek/csharp/Systems/ShieldControl.cs	
@@ -10,7 +10,7 @@ namespace SuperStarTrek.Systems
         private readonly Output _output;
         private readonly Input _input;
 
-        public ShieldControl(Enterprise enterprise, Output output, Input input)
+        internal ShieldControl(Enterprise enterprise, Output output, Input input)
             : base("Shield Control", Command.SHE, output)
         {
             _enterprise = enterprise;
@@ -18,7 +18,7 @@ namespace SuperStarTrek.Systems
             _input = input;
         }
 
-        public float ShieldEnergy { get; set; }
+        internal float ShieldEnergy { get; set; }
 
         protected override bool CanExecuteCommand() => IsOperational("{name} inoperable");
 
diff --git a/84 Super Star Trek/csharp/Systems/ShortRangeSensors.cs b/84 Super Star Trek/csharp/Systems/ShortRangeSensors.cs
index ad3929d1..c37028cb 100644
--- a/84 Super Star Trek/csharp/Systems/ShortRangeSensors.cs	
+++ b/84 Super Star Trek/csharp/Systems/ShortRangeSensors.cs	
@@ -16,7 +16,7 @@ namespace SuperStarTrek.Systems
         private readonly Game _game;
         private readonly Output _output;
 
-        public ShortRangeSensors(Enterprise enterprise, Galaxy galaxy, Game game, Output output)
+        internal ShortRangeSensors(Enterprise enterprise, Galaxy galaxy, Game game, Output output)
             : base("Short Range Sensors", Command.SRS, output)
         {
             _enterprise = enterprise;
@@ -47,7 +47,7 @@ namespace SuperStarTrek.Systems
             return CommandResult.Ok;
         }
 
-        public IEnumerable<string> GetStatusLines()
+        internal IEnumerable<string> GetStatusLines()
         {
             yield return $"Stardate           {_game.Stardate}";
             yield return $"Condition          {_enterprise.Condition}";
diff --git a/84 Super Star Trek/csharp/Systems/Subsystem.cs b/84 Super Star Trek/csharp/Systems/Subsystem.cs
index 9e5f3570..2e11e3e7 100644
--- a/84 Super Star Trek/csharp/Systems/Subsystem.cs	
+++ b/84 Super Star Trek/csharp/Systems/Subsystem.cs	
@@ -1,4 +1,3 @@
-using System;
 using SuperStarTrek.Commands;
 using SuperStarTrek.Space;
 
@@ -16,10 +15,10 @@ namespace SuperStarTrek.Systems
             _output = output;
         }
 
-        public string Name { get; }
-        public float Condition { get; private set; }
-        public bool IsDamaged => Condition < 0;
-        public Command Command { get; }
+        internal string Name { get; }
+        internal float Condition { get; private set; }
+        internal bool IsDamaged => Condition < 0;
+        internal Command Command { get; }
 
         protected virtual bool CanExecuteCommand() => true;
 
@@ -34,12 +33,12 @@ namespace SuperStarTrek.Systems
             return true;
         }
 
-        public CommandResult ExecuteCommand(Quadrant quadrant)
+        internal CommandResult ExecuteCommand(Quadrant quadrant)
             => CanExecuteCommand() ? ExecuteCommandCore(quadrant) : CommandResult.Ok;
 
         protected abstract CommandResult ExecuteCommandCore(Quadrant quadrant);
 
-        public virtual void Repair()
+        internal virtual void Repair()
         {
             if (IsDamaged)
             {
@@ -47,7 +46,7 @@ namespace SuperStarTrek.Systems
             }
         }
 
-        public virtual bool Repair(float repairWorkDone)
+        internal virtual bool Repair(float repairWorkDone)
         {
             if (IsDamaged)
             {
diff --git a/84 Super Star Trek/csharp/Systems/WarpEngines.cs b/84 Super Star Trek/csharp/Systems/WarpEngines.cs
index 0dcf396c..4203f4e8 100644
--- a/84 Super Star Trek/csharp/Systems/WarpEngines.cs	
+++ b/84 Super Star Trek/csharp/Systems/WarpEngines.cs	
@@ -11,7 +11,7 @@ namespace SuperStarTrek.Systems
         private readonly Output _output;
         private readonly Input _input;
 
-        public WarpEngines(Enterprise enterprise, Output output, Input input)
+        internal WarpEngines(Enterprise enterprise, Output output, Input input)
             : base("Warp Engines", Command.NAV, output)
         {
             _enterprise = enterprise;
diff --git a/84 Super Star Trek/csharp/Utils/DirectionAndDistance.cs b/84 Super Star Trek/csharp/Utils/DirectionAndDistance.cs
index 3fa9f4b8..65cb6a30 100644
--- a/84 Super Star Trek/csharp/Utils/DirectionAndDistance.cs	
+++ b/84 Super Star Trek/csharp/Utils/DirectionAndDistance.cs	
@@ -14,13 +14,13 @@ namespace SuperStarTrek.Utils
             _fromY = fromY;
         }
 
-        public static DirectionAndDistance From(Coordinates coordinates) => From(coordinates.X, coordinates.Y);
+        internal static DirectionAndDistance From(Coordinates coordinates) => From(coordinates.X, coordinates.Y);
 
-        public static DirectionAndDistance From(float x, float y) => new DirectionAndDistance(x, y);
+        internal static DirectionAndDistance From(float x, float y) => new DirectionAndDistance(x, y);
 
-        public (float Direction, float Distance) To(Coordinates coordinates) => To(coordinates.X, coordinates.Y);
+        internal (float Direction, float Distance) To(Coordinates coordinates) => To(coordinates.X, coordinates.Y);
 
-        public (float Direction, float Distance) To(float x, float y)
+        internal (float Direction, float Distance) To(float x, float y)
         {
             var deltaX = x - _fromX;
             var deltaY = y - _fromY;