Is the staircase metallic or wooden?
The staircase is metallic.
    src        edge_attr  dst
0     0   to the left of   11
1     0   to the left of    2
2     2  to the right of    0
3     2  to the right of    7
4     2  to the right of   15
5     2  to the right of    4
6     2  to the right of   11
7     2  to the right of    5
8     3  to the right of   13
9     4   to the left of    2
10    4  to the right of    9
11    5   to the left of    2
12    7   to the left of    2
13    8               in   14
14    9   to the left of    4
15   11  to the right of    0
16   11   to the left of    2
17   13   to the left of    3
18   15   to the left of    2