public void undoPerform(Position origin, Position destination, Piece capturedPiece)
{
Piece p = board.RemovePiece(destination);
p.MoveDecrement();
if (capturedPiece != null)
{
board.SetPiece(capturedPiece, destination);
capturedPieces.Remove(capturedPiece);
}
board.SetPiece(p, origin);
}