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