Does the sand that is white and brown seem to be wavy?
Yes, the sand is wavy.
    src        edge_attr  dst
0     1               on    0
1     3   to the left of   13
2     3   to the left of   10
3     5   to the left of    7
4     5   to the left of    9
5     5   to the left of    8
6     6   to the left of   13
7     7  to the right of    8
8     7  to the right of    5
9     8   to the left of    7
10    8  to the right of    5
11    9  to the right of    5
12   10  to the right of    3
13   10   to the left of   13
14   11   to the left of   13
15   13  to the right of    6
16   13  to the right of    3
17   13  to the right of   11
18   13  to the right of   10