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