Original Flow-style puzzles
Original boards from 5 × 5 up, each with exactly one solution, three hints and a step-by-step walkthrough that explains every move.
Newest puzzle · October 8, 2026
#20 Knife Ridge
Blue is the long color here. It starts beside the top-left corner, runs down the whole left edge, and later winds through the lower middle to reach its dot at row 10, column 9. The upper left packs into neat horizontal bands, but the center stays open for a long time and needs several rounds of thinking ahead.
12 × 12Expert
Every puzzle here starts as a random drawing. A generator lays a set of non-overlapping paths across the whole board and keeps only their two ends as the dots. The site's exact solver then proves that those dots allow exactly one solution. Boards with two or more answers are thrown away.
A board that passes still has to survive a second test. Another solver, limited to the techniques a person would use, must finish it without guessing. It can only make forced moves, fill squeezed cells, and try a move and follow its consequences until it fails. Its steps become the puzzle's walkthrough. Each step is then rewritten in plain language with AI assistance, checked against the position on the board, so it says plainly where to look and why the move has to happen. Each puzzle page also lists the techniques it uses, with links to the lessons that teach them.
What the levels mean
The difficulty comes from how much looking ahead that second solver needed.
- Beginner. Forced moves and squeezes solve the whole board. You never need to try anything.
- Intermediate. One to four moves need a short look ahead. You try a move, follow what it forces, and watch it fail.
- Advanced. Five or more moves need a short look ahead, or up to four need a deeper one, where the failure only shows after a second round of trying.
- Expert. Five or more moves need the deeper look, following one trial inside another.
Size and level are separate. A large Beginner board takes longer but never asks you to try anything, while a small Expert board can take far more thought. If you're new, how to play, forced moves and edges and corners cover everything a Beginner board needs. Thinking ahead is the lesson for the harder levels.
New boards go up every week. Each one has three hints, from where to look to the key step, so you can ask for as little help as you want.
8 more puzzles are already scheduled.