diff --git a/Qwirkle/QwirkleClassLibrary/Games/Game.cs b/Qwirkle/QwirkleClassLibrary/Games/Game.cs
index d7766a6..c374d43 100644
--- a/Qwirkle/QwirkleClassLibrary/Games/Game.cs
+++ b/Qwirkle/QwirkleClassLibrary/Games/Game.cs
@@ -474,7 +474,7 @@ namespace QwirkleClassLibrary.Games
                     previousTilesFound = true;
                 }
                 
-                if (cellUsed.Contains(extendedCell))
+                if (cellUsed.Contains(extendedCell!))
                 {
                     previousTilesFound = true;
                 }
@@ -570,27 +570,21 @@ namespace QwirkleClassLibrary.Games
                 {
                     nbTiles++;
 
-                    foreach (var t in checkdoubles)
+                    if(checkdoubles.Any(t => t.CompareTo(extendedCell.Tile) == 0))
                     {
-                        if (t.CompareTo(extendedCell.Tile) == 0)
-                        {
-                            return false;
-                        }
+                        return false;
                     }
 
                     checkdoubles.Add(extendedCell.Tile);
                 }
-                
-                if (extendedCell2?.Tile != null)
+
+                if (extendedCell2?.Tile == null) continue;
                 {
                     nbTiles++;
 
-                    foreach (var t in checkdoubles)
+                    if (checkdoubles.Any(t => t.CompareTo(extendedCell2.Tile) == 0))
                     {
-                        if (t.CompareTo(extendedCell2.Tile) == 0)
-                        {
-                            return false;
-                        }
+                        return false;
                     }
                     
                     checkdoubles.Add(extendedCell2.Tile);