# GRAPH STRUCTURE
# ---------------
# The graph has three similar blocks. Each is a subdivided K_4,4:
#
#   block 0: L = 0..3,   R = 4..7,   P = 24..39
#   block 1: L = 8..11,  R = 12..15, P = 40..55
#   block 2: L = 16..19, R = 20..23, P = 56..71
#
# Vertices 72..103 are connectors, called M vertices.
#
# Within a block, every P vertex lies between one L branch and one R branch.
# It also has two M neighbors. Every M vertex connects to one P in each block
# and to one other M vertex in the final matching section. This makes every
# vertex degree 4.
#
# The edge list is grouped as follows:
#   1. Internal L-P and R-P edges for blocks 0, 1, and 2 (96 edges)
#   2. Connector-to-P edges for blocks 0, 1, and 2 (96 edges)
#   3. Connector matching edges (16 edges)

# ============================================================================
# BLOCK 0 INTERNAL EDGES
# Vertices: L=0..3, R=4..7, P=24..39
# ============================================================================

# L-P edges: P(0,x,y) -- L(0,x)
0 24
0 25
0 26
0 27
1 28
1 29
1 30
1 31
2 32
2 33
2 34
2 35
3 36
3 37
3 38
3 39

# R-P edges: P(0,x,y) -- R(0,y)
4 24
4 28
4 32
4 36
5 25
5 29
5 33
5 37
6 26
6 30
6 34
6 38
7 27
7 31
7 35
7 39

# ============================================================================
# BLOCK 1 INTERNAL EDGES
# Vertices: L=8..11, R=12..15, P=40..55
# ============================================================================

# L-P edges: P(1,x,y) -- L(1,x)
8 40
8 41
8 42
8 43
9 44
9 45
9 46
9 47
10 48
10 49
10 50
10 51
11 52
11 53
11 54
11 55

# R-P edges: P(1,x,y) -- R(1,y)
12 40
12 44
12 48
12 52
13 41
13 45
13 49
13 53
14 42
14 46
14 50
14 54
15 43
15 47
15 51
15 55

# ============================================================================
# BLOCK 2 INTERNAL EDGES
# Vertices: L=16..19, R=20..23, P=56..71
# ============================================================================

# L-P edges: P(2,x,y) -- L(2,x)
16 56
16 57
16 58
16 59
17 60
17 61
17 62
17 63
18 64
18 65
18 66
18 67
19 68
19 69
19 70
19 71

# R-P edges: P(2,x,y) -- R(2,y)
20 56
20 60
20 64
20 68
21 57
21 61
21 65
21 69
22 58
22 62
22 66
22 70
23 59
23 63
23 67
23 71

# ============================================================================
# CONNECTOR-TO-P EDGES, BLOCK 0
# Each P(0,x,y) in 24..39 has exactly two M neighbors.
# ============================================================================
24 72
24 102
25 80
25 94
26 86
26 88
27 78
27 96
28 82
28 92
29 74
29 100
30 76
30 98
31 84
31 90
32 79
32 97
33 87
33 89
34 81
34 95
35 73
35 103
36 85
36 91
37 77
37 99
38 75
38 101
39 83
39 93

# ============================================================================
# CONNECTOR-TO-P EDGES, BLOCK 1
# Each P(1,x,y) in 40..55 has exactly two M neighbors.
# ============================================================================
40 72
40 93
41 73
41 92
42 77
42 88
43 76
43 89
44 75
44 94
45 74
45 95
46 78
46 91
47 79
47 90
48 84
48 99
49 85
49 98
50 80
50 103
51 81
51 102
52 87
52 96
53 86
53 97
54 83
54 100
55 82
55 101

# ============================================================================
# CONNECTOR-TO-P EDGES, BLOCK 2
# Each P(2,x,y) in 56..71 has exactly two M neighbors.
# ============================================================================
56 72
56 101
57 78
57 99
58 87
58 90
59 81
59 92
60 83
60 94
61 85
61 88
62 76
62 97
63 74
63 103
64 79
64 98
65 73
65 100
66 80
66 93
67 86
67 91
68 84
68 89
69 82
69 95
70 75
70 102
71 77
71 96

# ============================================================================
# CONNECTOR MATCHING EDGES
# These 16 edges pair connectors by flipping bit l.
# ============================================================================
72 74
73 75
76 78
77 79
80 82
81 83
84 86
85 87
88 90
89 91
92 94
93 95
96 98
97 99
100 102
101 103