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