Thanks for the reply! Yep, it worked, take a look at my solution.

Good kata, however, this error is outputing in the Javascript version:

   at perimeters
    at tests_code
        at Object.Test.describe```
        
There's not any mention of a 'fib' variable in the description and I've successfully completed the C# version using the exact same variable names and solution logic, so either I'm missing something or there's a potentially big issue which gets in the way of completing the kata.

I didn't know it was possible for users to peek at the contents of preloaded code, but I probably should have known better. Anyway, I've moved the actual solution to the test suite, so now the problem is actually solved. Thanks for pointing that out.

You've seen that that's the name of my pre-loaded solution function as it appeared in a past solution of mine, I guess. Thanks for reminding me that this name was already exposed, guess I'll have to switch it, pity.

Cool! Thanks for the feedback, glad you've liked it!

Yep; take a look at this stack exchange link:
http://math.stackexchange.com/questions/519845/modulo-of-a-negative-number

Random test cases now available for both Ruby and Javascript versions.

Cool, I've catched the error and it's been corrected.

Not exactly a duplicate; this kata asks for primes in a range, mine asks for all primes up to a number. Similar logic, yes, but not "duplicate".
Also, is this error in the Ruby or Javascript version?