public RowCol NeighborBR(RowCol cell) => new RowCol(Down(cell.Row), Right(cell.Col));
public RowCol NeighborBL(RowCol cell) => new RowCol(Down(cell.Row), Left(cell.Col));
public RowCol NeighborBB(RowCol cell) => new RowCol(Down(cell.Row), cell.Col);
public RowCol NeighborRR(RowCol cell) => new RowCol(cell.Row, Right(cell.Col));
public RowCol NeighborLL(RowCol cell) => new RowCol(cell.Row, Left(cell.Col));
public RowCol NeighborTR(RowCol cell) => new RowCol(Up(cell.Row), Right(cell.Col));
public RowCol NeighborTT(RowCol cell) => new RowCol(Up(cell.Row), cell.Col);
public RowCol NeighborTL(RowCol cell) => new RowCol(Up(cell.Row), Left(cell.Col));