public static CellCoordinates Subtract(CellCoordinates left, CellSpan right)
{
return(new CellCoordinates(left.X - right.X, left.Y - right.Y));
}
public static CellCoordinates Add(CellCoordinates left, CellSpan right)
{
return(new CellCoordinates(left.X + right.X, left.Y + right.Y));
}