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