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