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