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