public boolean containsCell(int x, int y){
            Edge edgeTop = Edge.obtain(x, y, Direction.RIGHT);
            Edge edgeLeft = Edge.obtain(x, y, Direction.BELOW);
            Edge edgeRight = Edge.obtain(x+1, y+1, Direction.ABOVE);
            Edge edgeBottom = Edge.obtain(x+1, y+1, Direction.LEFT);
            
            //if it contains all four edges            
            if(containsEdge(edgeTop) && containsEdge(edgeLeft) &&
                    containsEdge(edgeRight) && containsEdge(edgeBottom))
                return true;
            else
                return false;
        }