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About For every integer m ≥ 2, the following successor rule traces a Hamiltonian cycle of SB(m, 3), the digraph whose vertices are the strings xyz with 0 ≤ x, y, z < m and whose arcs go from xyz to yzx and to yz(x+1 mod m). With k = ⌊m/2⌋ + 1, the successor of xyz is yzx when y ≥ k and z < k, when y = 0 and z ≠ 0, or when z = 1 and y ≥ 2, except that for odd m ≥ 7 it is yz(x+1 mod m) when z = 1 and y ≥ k + 1; every other xyz has successor yz(x+1 mod m). Starting from 000, the first m³ steps of the walk visit m³ distinct vertices, which is every vertex, and the walk is back at 000 after m³ steps.

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