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