b11 := (2,3)(4,6)(5,7)(8,11)(9,12)(10,14)(13,18)(15,20)(16,21)(17,23)(19,26)
     (22,30)(27,34)(29,36)(31,39)(32,41)(33,42)(35,45)(37,47)(38,43)(44,51)
     (46,53)(48,54)(50,56)(55,59)(57,61)(58,62)(60,63);