public void MovePrev() => CurrentMove = PrevMove(CurrentMove);
public static WhoseMove PrevMove(WhoseMove move) => (move == WhoseMove.blackMove) ? WhoseMove.whiteArrow : (move - 1);
public void MoveNext() => CurrentMove = NextMove(CurrentMove);
public static WhoseMove NextMove(WhoseMove move) => (move == WhoseMove.whiteArrow) ? WhoseMove.blackMove : (move + 1);