digraph G {
"0" [style=bold];
"1" [style=bold];
"4" [style=bold];
"9" [style=bold];
0->2;
1->14;
2->13;
3->6;
3->14;
4->6;
4->7;
5->3;
6->5;
7->8;
8->4;
9->1;
9->16;
10->11;
11->12;
12->10;
12->9;
12->13;
13->0;
13->1;
14->15;
15->1;
15->6;
16->8;
16->11;
16->17;
17->4;
17->9;
}