X ( 1 , 27 , 2 , 26 ) X ( 3 , 29 , 4 , 28 ) X ( 5 , 31 , 6 , 30 ) X ( 7 , 33 , 8 , 32 ) X ( 9 , 35 , 10 , 34 ) X ( 11 , 37 , 12 , 36 ) X ( 13 , 39 , 14 , 38 ) X ( 15 , 41 , 16 , 40 ) X ( 17 , 43 , 18 , 42 ) X ( 19 , 45 , 20 , 44 ) X ( 21 , 47 , 22 , 46 ) X ( 23 , 49 , 24 , 48 ) X ( 25 , 1 , 26 , 50 ) X ( 27 , 3 , 28 , 2 ) X ( 29 , 5 , 30 , 4 ) X ( 31 , 7 , 32 , 6 ) X ( 33 , 9 , 34 , 8 ) X ( 35 , 11 , 36 , 10 ) X ( 37 , 13 , 38 , 12 ) X ( 39 , 15 , 40 , 14 ) X ( 41 , 17 , 42 , 16 ) X ( 43 , 19 , 44 , 18 ) X ( 45 , 21 , 46 , 20 ) X ( 47 , 23 , 48 , 22 ) X ( 49 , 25 , 50 , 24 ) {\displaystyle X(1,27,2,26)X(3,29,4,28)X(5,31,6,30)X(7,33,8,32)X(9,35,10,34)X(11,37,12,36)X(13,39,14,38)X(15,41,16,40)X(17,43,18,42)X(19,45,20,44)X(21,47,22,46)X(23,49,24,48)X(25,1,26,50)X(27,3,28,2)X(29,5,30,4)X(31,7,32,6)X(33,9,34,8)X(35,11,36,10)X(37,13,38,12)X(39,15,40,14)X(41,17,42,16)X(43,19,44,18)X(45,21,46,20)X(47,23,48,22)X(49,25,50,24)}