Which type of animal is this, a bear or an elephant?
This is an elephant.
   src        edge_attr  dst
0    0  to the right of   11
1    0  to the right of    3
2    0  to the right of    6
3    0  to the right of    9
4    3   to the left of    0
5    6   to the left of    0
6    9   to the left of    0
7   11   to the left of    0