Which shape is the clock?
The clock is round.
   src        edge_attr  dst
0    1  on the front of    4
1    1   to the left of    7
2    2            under    4
3    2            below    4
4    4  on the front of    3
5    4            above    2
6    6        on top of    3
7    7  to the right of    1