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 ( 11 , 19 , 12 , 18 ) X ( 13 , 21 , 14 , 20 ) X ( 15 , 6 , 16 , 7 ) X ( 17 , 1 , 18 , 22 ) X ( 19 , 15 , 20 , 14 ) X ( 21 , 13 , 22 , 12 ) {\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(11,19,12,18)X(13,21,14,20)X(15,6,16,7)X(17,1,18,22)X(19,15,20,14)X(21,13,22,12)}