Which side is the mat on?
The mat is on the left of the image.
    src        edge_attr  dst
0     0   to the left of   14
1     0   to the left of    1
2     1  to the right of    0
3     2   to the left of    5
4     2   to the left of    3
5     2   to the left of   12
6     3  to the right of    2
7     5  to the right of    7
8     5  to the right of    2
9     7   to the left of    5
10    7   to the left of   12
11   10               on    8
12   11               on    4
13   12  to the right of    2
14   12  to the right of    7
15   14  to the right of    0