C++ 2DArray Objects; Pointers and Array Problems

void Grid::extractArray( int** arr )
{
  for(int i = 0; i < xGrid ; ++i) {
    for (int j = 0; j < yGrid ; ++j) {
      squares[i][j] = arr[i][j];
    }
  }
}

void Grid::extractArray( const Piece & piece)
{
  for(int i = 0; i < piece.xGrid ; ++i) {
    for (int j = 0; j < piece.yGrid ; ++j) {
      squares[i][j] = arr[i][j];
    }
  }
}