Actually, rather than being polite and commenting on the article, I found myself distracted by liking the pirate/monkey problem. After taking it apart for a little while I think it’s possible to say it isn’t parody (as the link says) and find it solvable. The key, in my opinion, is to dispense with the chaos and recognize that the last statement defines (in a somewhat reverse order) what we may have solved (as preconditions) for us in the problems above. Not having some of the math makes it tricky (should I see significance in reversible primes?), but we’re allowed to state our assumptions, right? Assume enough away and it’s possible to frame anything.
For example, I might look at how one interprets the actual number of pirates per prisoner, which helps me answer why the rum’s gone. This is important to establish, with pirates. More seriously, may as well as recognize that some of the issues are independent (mass/liquid displacement to find poison and coin, river monkeys, and primes with an even leading digit can be separated), and rely on the final case statement to show that IF we assume the required conditions are met for, e.g., has everyone flipped the switch now, this resolves into what left as the actual puzzle. I.e., I don’t always need to know that the monkeys lie, just that it’s a precondition for part of another condition.
In the end, I became curious about who’s walking the plank. Since I don’t know if everyone’s a pirate, how many there are, and if this is part of a puzzle I haven’t seen, I came up with the need to knock everyone out (then we don’t care who’s prisoner/pirate/plankworthy) and effect the release. We’ll just solve what we can. Bribe the captors with the real coins, get each person catatonic on at least two bottles of that good, clean wine, wake up in the morgue, then (having already rigged the room switches for party strobe) give the party hats, fake coin, and bad wine to the primates…because there’s something not quite right about these monkeys and there are WAY too many of them trying to use our escape canoe.