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