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