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