Which kind of furniture is made of wood?
The furniture is a desk.
    src        edge_attr  dst
0     5  to the right of   11
1     6   to the left of    9
2     9  to the right of    6
3    11   to the left of    5
4    12  to the right of   16
5    12               on    3
6    12  to the right of   15
7    13   to the left of   14
8    14  to the right of   13
9    15  to the right of   16
10   15   to the left of   12
11   16               on    3
12   16   to the left of   15
13   16   to the left of   12