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