b11 := (2,4)(3,5)(6,8)(7,9)(10,14)(11,15)(12,16)(13,17)(18,25)(19,26)(20,27)
     (21,28)(23,29)(30,38)(31,39)(32,34)(33,40)(35,41)(36,42)(37,43)(44,50)
     (45,46)(47,48)(49,52)(53,55);