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