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