How large are the buildings?
The buildings are small.
    src        edge_attr  dst
0     0   to the left of    6
1     0   to the left of    5
2     0   to the left of    9
3     0   to the left of    7
4     0   to the left of   10
5     1  to the right of   13
6     1  to the right of    9
7     5               on    7
8     5  to the right of    0
9     5   to the left of   11
10    6               on    7
11    6  to the right of    0
12    7   to the left of   11
13    7  to the right of    0
14    9  to the right of    0
15    9   to the left of    1
16   10  to the right of    0
17   11  to the right of    5
18   11  to the right of    7
19   13   to the left of    1