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