X ( 1 , 23 , 2 , 22 ) X ( 3 , 25 , 4 , 24 ) X ( 5 , 27 , 6 , 26 ) X ( 7 , 29 , 8 , 28 ) X ( 9 , 31 , 10 , 30 ) X ( 11 , 33 , 12 , 32 ) X ( 13 , 35 , 14 , 34 ) X ( 15 , 37 , 16 , 36 ) X ( 17 , 39 , 18 , 38 ) X ( 19 , 41 , 20 , 40 ) X ( 21 , 1 , 22 , 42 ) X ( 23 , 3 , 24 , 2 ) X ( 25 , 5 , 26 , 4 ) X ( 27 , 7 , 28 , 6 ) X ( 29 , 9 , 30 , 8 ) X ( 31 , 11 , 32 , 10 ) X ( 33 , 13 , 34 , 12 ) X ( 35 , 15 , 36 , 14 ) X ( 37 , 17 , 38 , 16 ) X ( 39 , 19 , 40 , 18 ) X ( 41 , 21 , 42 , 20 ) {\displaystyle X(1,23,2,22)X(3,25,4,24)X(5,27,6,26)X(7,29,8,28)X(9,31,10,30)X(11,33,12,32)X(13,35,14,34)X(15,37,16,36)X(17,39,18,38)X(19,41,20,40)X(21,1,22,42)X(23,3,24,2)X(25,5,26,4)X(27,7,28,6)X(29,9,30,8)X(31,11,32,10)X(33,13,34,12)X(35,15,36,14)X(37,17,38,16)X(39,19,40,18)X(41,21,42,20)}
