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