An Elisp Challenge

Here’s a simple Elisp challenge suggested by a problem from by ProgrammingPraxis. We call one string a cycle of another if one string can be transformed into the other by a rotation of the characters. Note that this means

1. They have the same number of characters.
2. They have the same characters.
3. The characters are in the same order when considered as a cycle.

Thus, “abc” and “cab” are cycles of each other because if “abc” is rotated right by 1 (or left by 2) it equals “cab.” Notice that “abc” and “acb” are not cycles of each other even though they meet conditions 1 and 2.

The challenge is to write an Elisp function, cyclep, that tests whether two strings are cycles of each other.