Joel Neely schreef op 15-2-2015 om 13:04:

Hint:

So each of your has an odd number of lines.

What do all the center lines have in common?

There are all A -> C

What is common about all of the prefixes (groups of lines before the center) and suffixes (groups of lines following the center)?

on the second nothing

A -> B   compare with B -> C

On 3 disk


A -> B     B -> A
C -> B     B -> C

the second is the opposite of the first one.