diff --git a/Sharpasonne.Tests/Rules/SpaceIsEmptyRuleTests.cs b/Sharpasonne.Tests/Rules/SpaceIsEmptyRuleTests.cs
new file mode 100644
index 0000000..64d21d0
--- /dev/null
+++ b/Sharpasonne.Tests/Rules/SpaceIsEmptyRuleTests.cs
@@ -0,0 +1,26 @@
+using Sharpasonne.GameActions;
+using Sharpasonne.Rules;
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using Xunit;
+
+namespace Sharpasonne.Tests.Rules
+{
+    public class SpaceIsEmptyRuleTests
+    {
+        [Fact]
+        public void When_TileIsEmpty_Then_True()
+        {
+            Assert.True(new SpaceIsEmptyRule().Verify(new Engine(), new PlaceTileGameAction()));
+        }
+
+        [Fact]
+        public void When_TileIsEmpty_Then_False()
+        {
+            var engine = new Engine();
+
+            Assert.True(new SpaceIsEmptyRule().Verify(engine, new PlaceTileGameAction()));
+        }
+    }
+}
diff --git a/Sharpasonne/Engine.cs b/Sharpasonne/Engine.cs
index cd93b7c..ee8f8e5 100644
--- a/Sharpasonne/Engine.cs
+++ b/Sharpasonne/Engine.cs
@@ -2,6 +2,7 @@
 using System.Collections;
 using System.Collections.Immutable;
 using System.Linq;
+using System.Runtime.InteropServices;
 using JetBrains.Annotations;
 using Sharpasonne.Models;
 
@@ -12,17 +13,22 @@ public class Engine
     {
         public Board Board { get; } = new Board();
 
+        public Engine()
+        {
+        }
+
         public Engine(
             [NotNull] IImmutableQueue<IGameAction> gameActions,
             [NotNull] IImmutableDictionary<Type, IImmutableList<IRule>> rules)
         {
             var nonGameActions = rules.Keys
-                .Where(k => !k.GetInterfaces().Any(i => i == typeof(IGameAction)))
+                .Where(type => !typeof(IGameAction).IsAssignableFrom(type))
                 .ToList();
+
             if (nonGameActions.Any())
             {
                 var typeNames = string.Join(", ", nonGameActions.Select(t => t.FullName));
-                var message = $"'{typeNames}' don't implement {nameof(IGameAction)}";
+                var message = $"'{typeNames}' does not implement {nameof(IGameAction)}";
                 throw new ArgumentOutOfRangeException(message);
             }
         }
@@ -34,8 +40,4 @@ public Engine(
             
         }*/
     }
-
-    public interface IGameAction
-    {
-    }
 }
diff --git a/Sharpasonne/GameActions/PlaceTileGameAction.cs b/Sharpasonne/GameActions/PlaceTileGameAction.cs
new file mode 100644
index 0000000..1394f94
--- /dev/null
+++ b/Sharpasonne/GameActions/PlaceTileGameAction.cs
@@ -0,0 +1,9 @@
+using Sharpasonne;
+using Sharpasonne.Models;
+
+namespace Sharpasonne.GameActions
+{
+    public class PlaceTileGameAction : IGameAction
+    {
+    }
+}
diff --git a/Sharpasonne/IGameAction.cs b/Sharpasonne/IGameAction.cs
new file mode 100644
index 0000000..7a9c322
--- /dev/null
+++ b/Sharpasonne/IGameAction.cs
@@ -0,0 +1,6 @@
+namespace Sharpasonne
+{
+    public interface IGameAction
+    {
+    }
+}
\ No newline at end of file
diff --git a/Sharpasonne/Rules/SpaceIsEmptyRule.cs b/Sharpasonne/Rules/SpaceIsEmptyRule.cs
new file mode 100644
index 0000000..e1835a1
--- /dev/null
+++ b/Sharpasonne/Rules/SpaceIsEmptyRule.cs
@@ -0,0 +1,14 @@
+using Sharpasonne;
+using Sharpasonne.Models;
+
+namespace Sharpasonne.Rules
+{
+    public class SpaceIsEmptyRule : IRule
+    {
+        public bool Verify<T>(Engine engine, T gameAction)
+            where T : IGameAction
+        {
+            return true;
+        }
+    }
+}