Which place is it?
It is a field.
    src        edge_attr  dst
0     0   to the left of    6
1     0  to the right of    2
2     2   to the left of    0
3     3  to the right of   12
4     3   to the left of    8
5     4   to the left of    9
6     5     covered with    8
7     6  to the right of    0
8     6  to the right of   11
9     7               of   11
10    8  to the right of   11
11    8  to the right of    3
12    9               of   11
13    9  to the right of    4
14   11   to the left of    8
15   11   to the left of    6
16   12   to the left of    3
17   12               of   11