Which color is this fence?
The fence is black.
    src        edge_attr  dst
0     0               on   15
1     0  to the right of    4
2     0  to the right of   13
3     1  to the right of   12
4     1  to the right of    7
5     2  to the right of    9
6     2  to the right of   14
7     2   to the left of    3
8     3  to the right of    2
9     4   to the left of    0
10    4   to the left of   15
11    4   to the left of   14
12    4   to the left of    9
13    5   to the left of    8
14    7   to the left of   15
15    7   to the left of    1
16    8  to the right of    5
17    9  to the right of    4
18    9   to the left of    2
19   12   to the left of    1
20   13   to the left of    0
21   14   to the left of    2
22   14  to the right of    4
23   14               in   11
24   15  to the right of    4
25   15  to the right of    7
26   16               on    6