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