What makes up the brown ground, clay or rock?
The ground is made of clay.
     src        edge_attr  dst
0      0  to the right of   30
1      0  to the right of   18
2      0  to the right of   16
3      0   to the left of   29
4      0   to the left of   22
..   ...              ...  ...
192   30   to the left of   15
193   30   to the left of    8
194   30  to the right of   13
195   30   to the left of   12
196   30  to the right of   10

[197 rows x 3 columns]