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