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