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