There seems to be a problem with the way I generated the map for the last test case. There are actually multiple roads leading from 12 to 66 and from 66 to 99 on the test map. Editing the test case would be the right thing to do, but I'm too lazy for that, so I'll edit the description instead.

They are less than 2 (and not prime). A prime is a natural number greater than 1 that has no positive divisors other than 1 and itself.

n-dimensional Manhattan, anyone?

Nice Kata, but don't you mean ignore relativistic effects rather than relative effects?

Duplicates http://www.codewars.com/dojo/katas/5244ab738978478c1800002e, doesn't it?

Hint: It doesn't work if your solution modifies the recipe. The random test cases all use the same recipe object to compute expected outcomes, AFTER it is passed to the solution function.

Neat && trick. I've just gotten used to obj || "some value" but somehow never thought about using (abusing?) the && operator this way.

Evil wizards should be worth 11 according to description, 10 according t o the tests!

Ok, matches the description now which makes it a lot easier. I changed my recommendation to "ready".

Ah, the poetic brute force approach.