Are there any clocks or towers?
Yes, there is a clock.
    src        edge_attr  dst
0     0   to the left of   10
1     1   to the left of   10
2     1  to the right of    8
3     4   to the left of   10
4     4  to the right of    6
5     4  to the right of   11
6     6   to the left of    4
7     7   to the left of   10
8     8   to the left of   10
9     8   to the left of    1
10    8  to the right of   12
11   10  to the right of    4
12   10  to the right of    7
13   10  to the right of    8
14   10  to the right of    0
15   10  to the right of    1
16   11   to the left of    4
17   12   to the left of    8