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