What's the clock on?
The clock is on the clock tower.
   src        edge_attr  dst
0    0  to the right of    4
1    0  to the right of    1
2    0  to the right of    8
3    1               of    4
4    1   to the left of    0
5    3               on    0
6    4   to the left of    0
7    8   to the left of    0