If you came up with a testing challenge in particular, I'd be interested to see it! I wouldn't use this as your only feeder--as someone else mentioned, puzzle

If you came up with a testing challenge in particular, I'd be interested to see it! I wouldn't use this as your only feeder--as someone else mentioned, puzzle affinity isn't going to be a 100% crossover with the people you want to track. I'd see a puzzle as one of a few tactics to all try simultaneously. That's probably another argument against making something like this mandatory--it essentially becomes your only feeder/filter if everyone goes through it.