This problem follows on from Twisting and Turning and More Twisting and Turning in which twisting has the effect of adding 1 and turning transforms any number into the negative of its reciprocal.


We can start at 0 and end up at any fraction of the form
n n+1



by following the sequence: twist, twist, twist, ... , twist, twist, turn, twist

eg. to end up at 4 5 :

twist, twist, twist, twist, twist, turn, twist

to produce:
0,1,2,3,4,5, -1 5 , 4 5

Check you can reach 9 10



The sequence twist, twist, turn, twist, twist, turn, twist, twist, turn, ... , twist, twist, turn, twist

will lead us from 0 to all the fractions of the form
1 n


eg. to end up at 1 5 (and 1 2 , 1 3 and 1 4 along the way):

twist, twist, turn, twist, twist, turn, twist, twist, turn, twist, twist, turn, twist

to produce:
0, 1, 2, -1 2 , 1 2 , 3 2 , -2 3 , 1 3 , 4 3 , -3 4 , 1 4 , 5 4 , -4 5 , 1 5

Check you can reach 1 10


Can you find other sequences of twists and turns that lead to special fractions?

Is it possible to start at 0 and end up at any fraction?