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