// Cells and their vertices.
#0={0}
#1={1,2,3,5,7}
#2={4,6,8}

// Induced graph on cells.
#0:.
#1:->#0.
#2:->#1.

// Individual cells.
// cell #0:
0[0]: {}

// cell #1:
0[1]: {2} --> 1,2
1[2]: {1} --> 0
2[3]: {3} --> 0,3
3[5]: {2} --> 2,4
4[7]: {1} --> 3

// cell #2:
0[4]: {1,3} --> 1,2
1[6]: {1,2} --> 0
2[8]: {2} --> 0