text: a = [0, 1, 2, 3, 4, 5, 6, 7]
  b = []
  i = 0
  while i < len(a) - 2:
      a2 = a[i + 1:]
      j = 0
      while j < len(a2) - 1:
          a3 = a2[j + 1:]
          k = 0
          while k < len(a3):
              b.append([a[i], a2[j], a3[k]])
              k += 1
          j += 1
      i += 1
  for x in b:
      print(x)
  