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