What are the devices in front of the wall?
The devices are computers.
    src        edge_attr  dst
0     0   to the left of    4
1     0   to the left of   10
2     0      in front of    2
3     0               by    3
4     0             near    7
5     0   to the left of   14
6     0  to the right of   13
7     0               on   15
8     0   to the left of    6
9     1               by   11
10    1  to the right of    9
11    1  to the right of    4
12    1  to the right of   12
13    1               on   15
14    2           behind    0
15    3               on   15
16    3   to the left of   14
17    3   to the left of   10
18    4               by    0
19    4               on   15
20    4   to the left of   12
21    4   to the left of    1
22    4   to the left of    9
23    4  to the right of    0
24    4   to the left of   11
25    5               by   15
26    5   to the left of    8
27    5   to the left of    7
28    6               on   15
29    6   to the left of   12
30    6  to the right of    0
31    7             near    0
32    7  to the right of    5
33    7               on    8
34    8  to the right of    5
35    9   to the left of    1
36    9               on   15
37    9  to the right of    4
38    9            above   12
39   10  to the right of   14
40   10  to the right of    3
41   10               on   15
42   10  to the right of    0
43   11  to the right of    4
44   11               on   15
45   12  to the right of    6
46   12               on   15
47   12  to the right of    4
48   12   to the left of    1
49   12            under    9
50   13   to the left of    0
51   13               on   15
52   14  to the right of    3
53   14  to the right of    0
54   14   to the left of   10