Maps are more generic as well as cells.

ConsoleApp/Maps/ISquareCell.cs

@@ -2,7 +2,7 @@ namespace ConsoleApp.Maps
 {
     public interface ISquareCell : ICell
     {
-        int X { get; }
-        int Y { get; }
+        new int X { get; }
+        new int Y { get; }
     }
 }