Wednesday, 6 May 2026

Lavaloid

Today's Yin-Yang (Matryoshka) was originally meant to be perfectly anti-symmetric, but I bumped into the puzzle while setting it and now one of the rectangles is off-center.

Matryoshka also has a different meaning in logic puzzles: It also refers to a puzzle many layers, such that when its outer layer is removed, it's still a valid puzzle. It differs with today's puzzle as it is actually several unique puzzles, while today's GAPP is only a single puzzle where the inner layers don't necessarily have a unique solution by themselves. Here's an example by Nikolai Beluhov: https://www.gmpuzzles.com/blog/2013/11/sunday-surprise-9-matryoshka-fillomino/

Previous standard Yin-Yang by Jovi: Archive: Friday, 27 February 2026

Rules:
- Place a circle into each cell of the grid - some white and some black - such that all circles of the same type must lie in cells forming one orthogonally connected area. No 2x2 region may contain all one type of circle.
- Some rectangles (or squares) are highlighted in the grid. Each rectangle must also be a valid Yin-Yang puzzle, and so must obey the same rules.

GAPP 101: There must be at most one orthogonally connected group of each circle type along the border. If there was more than one group of black circles, for instance, the group of white circles between them would be cut off from the rest of the white circles due to the black circles connecting across them.

Finish the puzzle in 2:00 or less for a Speedy Sloth 🦥!
Finish the puzzle in 4:00 or less for a Quick Crab 🦀!
Finish with any time at all for a Recursive Racket-tailed Roller 🐦!

Example (Penpa+): https://tinyurl.com/54a2wtde
Puzzle (Penpa+): https://tinyurl.com/44kmexyc