Rough layout

   0  1  2

   3  4  5  6

 7  8  9  10  11

    12 13


The graph

0 3
1 0
1 5
2 5
2 6
3 1
3 7
4 1
4 9
5 2
6 5
6 11
7 4
7 8
8 7
8 12
9 8
9 13
10 5
10 11
11 5
12 13
13 12