z1 := (1,2,4)(3,5,8)(6,9,12)(10,13,17)(11,14,19)(15,20,26)(16,21,28)(18,23,31)
     (22,29,36)(24,32,40)(25,33,41)(27,35,44)(30,38,46)(34,42,51)(39,47,53)
     (43,52,60)(45,54,62)(48,50,55)(49,57,58)(56,61,63);