hamilton/grid4.dot

digraph {
dpi=200
node [shape=circle, style=filled]
0  ->  1
1  ->  0
1  ->  2
2  ->  1
2  ->  3
3  ->  2
3  ->  4
4  ->  3
4  ->  5
5  ->  4
5  ->  6
5  ->  14
6  ->  5
6  ->  7
7  ->  6
7  ->  8
7  ->  14
8  ->  7
8  ->  9
8  ->  13
9  ->  8
9  ->  10
9  ->  12
10  ->  9
10  ->  11
11  ->  10
11  ->  12
11  ->  15
12  ->  9
12  ->  11
12  ->  13
12  ->  16
13  ->  8
13  ->  12
13  ->  14
13  ->  17
14  ->  5
14  ->  7
14  ->  13
15  ->  11
15  ->  16
16  ->  12
16  ->  15
16  ->  17
17  ->  13
17  ->  16
}