Which color is the book that is to the right of the other book?
The book is red.
    src        edge_attr  dst
0     0      sleeping in    4
1     0         lying on    4
2     0  to the right of    5
3     0         lying in    4
4     1  to the right of   10
5     1               on    4
6     2   to the left of    3
7     3  to the right of    2
8     4      in front of   10
9     5   to the left of    0
10    7               on   10
11    7   to the left of   11
12   10   to the left of    1
13   10           behind    4
14   11  to the right of    7