Puzzles #662 & #663 - 24HPC Loops (Nagare, All or Nothing)

I also contributed several puzzles to the Puzzlers Club rounds at the 2024 24 Hour Puzzle Championship this year. We authored two rounds, each with 24 puzzles. The first round had one puzzle themed on each Greek letter, while the second round was a double zodiac (signs and animals).

I don't remember why Psi got a Nagare puzzle. My notes apparently say it's a play on wind/pressure/Pounds per Square Inch/PSI/psi, but that's a huge stretch. Despite the size, this one is only worth 25 points, because the type is honestly pretty tame and hard to make difficult. Can't really complain too much though, as this was a struggle to make work at all honestly.

puzz.link interface

For Omega, yyao had made a pretty basic Simple Loop with a note to replace the slot in the case of a better puzzle. I thought All or Nothing would be a pretty fitting genre and had even written it down as an idea locally, so as construction was wrapping up and the round was tending a bit easier than desired, I made one to finish off the Greek round. I still have one puzzle left to share from the round, though...

puzz.link interface

Puzzle #258 - Crosswind (Crossing Nagare)

How many times has the first puzzle of a genre I've posted been a variant of that puzzle? I actually don't know. Anyway, here's a Nagare puzzle where the loop is allowed to cross. Note that crossing through the "wind" would not be allowed, as one of the crossing lines would not be pushed, and that crossing on a black arrow would also not be allowed, as it would then be exited in a direction other than where it's pointing.

puzz.link interface      penpa interface

I think this variant is a bit more interesting than the standard type, though it does lose some neat directionality arguments from the fact that the loop can cross. In a standard Nagare, the two adjacent down arrows would be an instant contradiction!

Update: the original puzzle had 2 solutions, this has since been fixed.