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