X ( 1 , 6 , 2 , 7 ) X ( 3 , 12 , 4 , 13 ) X ( 5 , 14 , 6 , 15 ) X ( 7 , 17 , 8 , 16 ) X ( 9 , 19 , 10 , 18 ) X ( 11 , 2 , 12 , 3 ) X ( 13 , 4 , 14 , 5 ) X ( 15 , 1 , 16 , 20 ) X ( 17 , 11 , 18 , 10 ) X ( 19 , 9 , 20 , 8 ) {\displaystyle X(1,6,2,7)X(3,12,4,13)X(5,14,6,15)X(7,17,8,16)X(9,19,10,18)X(11,2,12,3)X(13,4,14,5)X(15,1,16,20)X(17,11,18,10)X(19,9,20,8)}
