[kafkaesq]

It's what you might call a "halfway algorithm" -- yes it needs some major fudging baked in (because from what I understand you can't do things iteratively in CSS). But it does, intrinsically, compute the primes. And the point is it demonstrates a kind of computation one normally wouldn't think was even possible with CSS (that is: not that you'd rule it out as beyond the computational reach of CSS; but it's definitely the sort of computation you normally wouldn't think to do with CSS).

So I'd say it's definitely a valid hack.