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