edge

Figure 4b

Figure 4c

Figure 4d

0

(0, 1, X, a, Y)

(0, 1, Y, a, X)

(0, 1, X, a, X)

1

(1, 2, Y, b, X)

(1, 2, X, a, X)

(1, 2, X, a, Y)

2

(2, 0, X, a, X)

(2, 0, X, b, Y)

(2, 0, Y, b, X)

3

(2, 3, X, c, Z)

(2, 3, X, c, Z)

(2, 3, Y, b, Z)

4

(3, 1, Z, b, Y)

(3, 0, Z, b, Y)

(3, 0, Z, c, X)

5

(1, 4, Y, d, Z)

(0, 4, Y, d, Z)

(2, 4, Y, d, Z)

0

(0, 1, X, a, Y)

(0, 1, Y, a, X)

(0, 1, X, a, X)