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