Which color is the sand?
The sand is white.
    src        edge_attr  dst
0     0               on    3
1     0  to the right of    3
2     1   to the left of    4
3     1               on    3
4     1  to the right of    3
5     1   to the left of    2
6     2  to the right of    1
7     3   to the left of    0
8     3   to the left of    1
9     3             near    7
10    3   to the left of    4
11    4  to the right of    1
12    4               in    3
13    4  to the right of    3
14    4         stuck in    3
15    4               on    3
16    7          next to    3
17    7             near    3