X ( 2 , 22 , 3 , 21 ) X ( 3 , 41 , 4 , 40 ) X ( 6 , 26 , 7 , 25 ) X ( 7 , 45 , 8 , 44 ) X ( 10 , 30 , 11 , 29 ) X ( 11 , 49 , 12 , 48 ) X ( 14 , 34 , 15 , 33 ) X ( 15 , 53 , 16 , 52 ) X ( 18 , 38 , 19 , 37 ) X ( 19 , 1 , 20 , 56 ) X ( 22 , 42 , 23 , 41 ) X ( 23 , 5 , 24 , 4 ) X ( 26 , 46 , 27 , 45 ) X ( 27 , 9 , 28 , 8 ) X ( 30 , 50 , 31 , 49 ) X ( 31 , 13 , 32 , 12 ) X ( 34 , 54 , 35 , 53 ) X ( 35 , 17 , 36 , 16 ) X ( 38 , 2 , 39 , 1 ) X ( 39 , 21 , 40 , 20 ) X ( 42 , 6 , 43 , 5 ) X ( 43 , 25 , 44 , 24 ) X ( 46 , 10 , 47 , 9 ) X ( 47 , 29 , 48 , 28 ) X ( 50 , 14 , 51 , 13 ) X ( 51 , 33 , 52 , 32 ) X ( 54 , 18 , 55 , 17 ) X ( 55 , 37 , 56 , 36 ) {\displaystyle X(2,22,3,21)X(3,41,4,40)X(6,26,7,25)X(7,45,8,44)X(10,30,11,29)X(11,49,12,48)X(14,34,15,33)X(15,53,16,52)X(18,38,19,37)X(19,1,20,56)X(22,42,23,41)X(23,5,24,4)X(26,46,27,45)X(27,9,28,8)X(30,50,31,49)X(31,13,32,12)X(34,54,35,53)X(35,17,36,16)X(38,2,39,1)X(39,21,40,20)X(42,6,43,5)X(43,25,44,24)X(46,10,47,9)X(47,29,48,28)X(50,14,51,13)X(51,33,52,32)X(54,18,55,17)X(55,37,56,36)}