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