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