Pell Puzzles

About Pell Puzzles

Pell Puzzles is a minimalist black-and-white logic puzzle by achromath, a small site that also hosts tennis analytics. It has run since December 2025, with one dated puzzle per day scheduled in advance for everyone.

The rules fit on a card. Fill the 6x6 grid by creating exactly eight paths with unique lengths, 1, 2, 3, 4, 5, 6, 7 and 8. A length-1 path is just a marked X; every other path connects exactly one X to one O. You may not create a pool (a solid 2x2 block of path cells), and a path cannot touch itself, though diagonal contact is fine. You draw by dragging from an empty cell or endpoint, break a path by clicking a segment, and merge two paths by dragging one endpoint into another.

A timer and move counter run while you solve. Afterwards you see your solve order and can share the result. The archive lists every day with your time, the fastest and median times and the solve rate, and a global leaderboard ranks players by solves and fast solves. You can play as a guest or sign in to sync progress.

It suits fans of Nikoli-style pencil puzzles and LinkedIn's Zip who want something short and sharp each day.

How to play Pell Puzzles

1. Open Pell Puzzles and choose Daily Puzzle.
2. Drag from an X or O to draw paths; click an X alone for the length-1 path.
3. Make exactly eight paths with lengths 1 to 8, each joining one X to one O.
4. Avoid 2x2 blocks and paths touching themselves, then check your time against the archive and leaderboard.

Tips

• Place the length-8 and length-7 paths early; they have the fewest ways to fit.
• Watch for 2x2 pools when two paths run side by side.
• Use merge to join two half-paths instead of redrawing.

Questions