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