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