text: m_rows = [
  [ 8,  2, 22, 97, 38, 15,  0, 40,  0, 75,  4,  5,  7, 78, 52, 12, 50, 77, 91, 8],
  [49, 49, 99, 40, 17, 81, 18, 57, 60, 87, 17, 40, 98, 43, 69, 48,  4, 56, 62, 0],
  [81, 49, 31, 73, 55, 79, 14, 29, 93, 71, 40, 67, 53, 88, 30,  3, 49, 13, 36, 65],
  [52, 70, 95, 23,  4, 60, 11, 42, 69, 24, 68, 56,  1, 32, 56, 71, 37,  2, 36, 91],
  [22, 31, 16, 71, 51, 67, 63, 89, 41, 92, 36, 54, 22, 40, 40, 28, 66, 33, 13, 80],
  [24, 47, 32, 60, 99,  3, 45,  2, 44, 75, 33, 53, 78, 36, 84, 20, 35, 17, 12, 50],
  [32, 98, 81, 28, 64, 23, 67, 10, 26, 38, 40, 67, 59, 54, 70, 66, 18, 38, 64, 70],
  [67, 26, 20, 68,  2, 62, 12, 20, 95, 63, 94, 39, 63,  8, 40, 91, 66, 49, 94, 21],
  [24, 55, 58,  5, 66, 73, 99, 26, 97, 17, 78, 78, 96, 83, 14, 88, 34, 89, 63, 72],
  [21, 36, 23,  9, 75,  0, 76, 44, 20, 45, 35, 14,  0, 61, 33, 97, 34, 31, 33, 95],
  [78, 17, 53, 28, 22, 75, 31, 67, 15, 94,  3, 80,  4, 62, 16, 14,  9, 53, 56, 92],
  [16, 39,  5, 42, 96, 35, 31, 47, 55, 58, 88, 24,  0, 17, 54, 24, 36, 29, 85, 57],
  [86, 56,  0, 48, 35, 71, 89,  7,  5, 44, 44, 37, 44, 60, 21, 58, 51, 54, 17, 58],
  [19, 80, 81, 68,  5, 94, 47, 69, 28, 73, 92, 13, 86, 52, 17, 77,  4, 89, 55, 40],
  [ 4, 52,  8, 83, 97, 35, 99, 16,  7, 97, 57, 32, 16, 26, 26, 79, 33, 27, 98, 66],
  [88, 36, 68, 87, 57, 62, 20, 72,  3, 46, 33, 67, 46, 55, 12, 32, 63, 93, 53, 69],
  [ 4, 42, 16, 73, 38, 25, 39, 11, 24, 94, 72, 18,  8, 46, 29, 32, 40, 62, 76, 36],
  [20, 69, 36, 41, 72, 30, 23, 88, 34, 62, 99, 69, 82, 67, 59, 85, 74,  4, 36, 16],
  [20, 73, 35, 29, 78, 31, 90,  1, 74, 31, 49, 71, 48, 86, 81, 16, 23, 57,  5, 54],
  [ 1, 70, 54, 71, 83, 51, 54, 69, 16, 92, 33, 48, 61, 43, 52,  1, 89, 19, 67, 48]
  ]
  m_columns = []
  m_left_diagonals = []
  m_right_diagonals = []
  m_rows_reverse = list(reversed(m_rows))
  
  m_size = len(m_rows[1])
  
  # Construct the columns
  for i in xrange(0, m_size):
    column = []
    
    for j in xrange(0, m_size):
      column.append(m_rows[j][i])
    
    m_columns.append(column)
    
  # Construct the diagonals (\: left, /: right)
  l_diagonal = []
  r_diagonal = []
  
  for i in xrange(0, m_size):
    l_diagonal1 = []
    r_diagonal1 = []
    l_diagonal2 = []
    r_diagonal2 = []
    
    for j in xrange(i, m_size):
      l_diagonal1.append(m_rows[j][j-i])
      l_diagonal2.append(m_rows[j-i][j])
      r_diagonal1.append(m_rows_reverse[j][j-i])
      r_diagonal2.append(m_rows_reverse[j-i][j])
      
    m_left_diagonals.append(l_diagonal1)
    m_left_diagonals.append(l_diagonal2)
    m_right_diagonals.append(r_diagonal1)
    m_right_diagonals.append(r_diagonal2)
  
  lines = m_columns + m_rows + m_left_diagonals + m_right_diagonals
  lines = filter(lambda x: len(x) > 3, lines)
  lines_size = len(lines)
  
  for i in xrange(0,lines_size):
    line = lines.pop(0)
    last_j = 0
    
    for j in xrange(0, len(line)):
      if line[j] == 0:
        if abs(last_j - j) >= 4:
          lines.append(line[last_j:j])
        last_j = j + 1
      elif last_j == 0 and j + 1 == len(line):
        lines.append(line)
  
  max_product = 0
  max_line = []
  
  for i in xrange(0, len(lines)):
    line = lines[i]
    print "---"
    print line
    for j in xrange(0,len(lines[i])-3):
      subline = line[j:j+4]
      print '-'
      print subline
      product = reduce(lambda x,y: x*y, subline, 1)
      print product
      if product > max_product:
        max_product = product
        max_line = subline
        
  
  print "Max product: ", max_product
  print subline
        