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