class MyMatrix
  def self.rotate(matrix)
    orig_rows = matrix.size
    orig_cols = matrix[0].size
    # Note, read Array.new carefully - size references to the *same* obj
    rm = Array.new(orig_cols) { Array.new(orig_rows, 0) }
    matrix.each_with_index do |row, row_idx|
      new_row = orig_cols - 1
      row.each_with_index do |col, col_idx|
        new_col = row_idx
        rm[new_row][new_col] = col
        new_row -= 1
      end
    end
    return rm
  end
end