Do the rocks that look gray have small size?
No, the rocks are large.
    src        edge_attr  dst
0     2    surrounded by    6
1     3     covered with    6
2     3       covered in    6
3     3       covered by    6
4     5               on    6
5     5  to the right of    9
6     6         covering    3
7     7   to the left of    9
8     8     covered with    6
9     9  to the right of    7
10    9   to the left of    5