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