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