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