gistfile1.c

int cube_edge_vertex_index(int index) {
  // a represents orientation
  int a = index >> 3;
  int b = index & 7;
  // rotate b
  int c = b >> (3 - a);
  int d = (b << a) & 7;
  return c | d;
}

// 0 1 2 3 4 5 6 7
// 0 2 4 6 1 3 5 7
// 0 4 1 5 2 6 3 7

gistfile2.py

[(i % 8 * 9 >> i / 8) % 8 for i in range(24)]

# [0, 1, 2, 3, 4, 5, 6, 7,
#  0, 4, 1, 5, 2, 6, 3, 7,
#  0, 2, 4, 6, 1, 3, 5, 7]