Circular Primes - Project Euler

Basically, you generate prime numbers for a given range, then you compute all the rotations for that number, for example "197" can be "197", "971", or "719", then determine if all the rotations are prime numbers. If they are, it is a circular prime.

"197" -> "197", "971", "719"
"11" -> "11"
"13" -> "13", "31"