What's located on top of the table?
The placemat is on top of the table.
    src        edge_attr  dst
0     0        on top of   10
1     0   to the left of   17
2     0   to the left of   15
3     0   to the left of   11
4     0   to the left of    2
..  ...              ...  ...
68   19        on top of    5
69   20  to the right of    1
70   20  to the right of    5
71   20  to the right of    6
72   20  to the right of    0

[73 rows x 3 columns]