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