X ( 2 , 5 , 3 , 6 ) X ( 3 , 13 , 4 , 12 ) X ( 6 , 1 , 7 , 2 ) X ( 7 , 17 , 8 , 16 ) X ( 9 , 20 , 10 , 21 ) X ( 11 , 1 , 12 , 4 ) X ( 13 , 19 , 14 , 18 ) X ( 15 , 5 , 16 , 10 ) X ( 17 , 11 , 18 , 22 ) X ( 19 , 15 , 20 , 14 ) X ( 21 , 8 , 22 , 9 ) {\displaystyle X(2,5,3,6)X(3,13,4,12)X(6,1,7,2)X(7,17,8,16)X(9,20,10,21)X(11,1,12,4)X(13,19,14,18)X(15,5,16,10)X(17,11,18,22)X(19,15,20,14)X(21,8,22,9)}