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