How big is the ladder in the bottom of the image?
The ladder is small.
    src        edge_attr  dst
0     0   to the left of   17
1     1  to the right of    2
2     2   to the left of    1
3     2  to the right of   13
4     2   to the left of    9
5     3  to the right of   15
6     3  to the right of    4
7     4   to the left of   12
8     4  to the right of   15
9     4   to the left of    3
10    6   to the left of   16
11    6   to the left of   10
12    9  to the right of    2
13   10  to the right of   16
14   10  to the right of    6
15   11   to the left of   15
16   12  to the right of   15
17   12  to the right of    4
18   13   to the left of    2
19   15  to the right of   11
20   15   to the left of    3
21   15               of    2
22   15   to the left of   12
23   15   to the left of    4
24   16  to the right of    6
25   16   to the left of   10
26   17  to the right of    0