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