What's the zebra in front of?
The zebra is in front of the tree.
    src        edge_attr  dst
0     0   to the left of    1
1     1           behind    8
2     1  to the right of    4
3     1  to the right of    8
4     1  to the right of    5
5     1  to the right of    0
6     1  to the right of   10
7     1  to the right of    9
8     3   to the left of    7
9     4   to the left of    1
10    4  to the right of    6
11    4  to the right of   10
12    5  to the right of   10
13    5   to the left of    1
14    6   to the left of    4
15    7  to the right of    3
16    8   to the left of    1
17    8      standing in    2
18    8      in front of    1
19    9   to the left of    1
20   10   to the left of    4
21   10   to the left of    1
22   10   to the left of    5