Are there shelves or desks that are made of metal?
Yes, the desk is made of metal.
     src       edge_attr  dst
0      0  to the left of    2
1      1  to the left of   21
2      1  to the left of   25
3      1  to the left of   24
4      1  to the left of   15
..   ...             ...  ...
139   30  to the left of   16
140   32  to the left of    6
141   32  to the left of    2
142   32              on   22
143   32  to the left of   23

[144 rows x 3 columns]