Ten or more years ago a web search (I think for something like Python lambdas) popped up something like this. After I solved all the puzzles the payoff was an interview at Google.

However, I would have had to take time off work and get myself to a Google office in another state for the interview, and even if I got a job offer (hardly guaranteed) I'd have to move.

I was pretty pretty pissed off, it felt like a complete bait-and-switch.

I mean, if you're going to the trouble of setting up an elaborate puzzle gauntlet as a recruiting tool, shouldn't you at least pay for travel and lodging to get to the in-person interview?

Not to mention that, as I found out later, my lack of a degree would have disqualified me from receiving an offer.