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