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