What is Pell Puzzles?
Pell Puzzles is a grid-based logic puzzle played on a 6x6 board. The goal is to fill the entire grid with exactly eight paths of unique lengths from 1 to 8. Most paths connect an X endpoint to an O endpoint; the single-cell path is marked by an X alone.
How to play Pell Puzzles
- Examine the 6x6 grid. It contains eight Xs and seven Os, plus empty cells. The board always holds these fixed markers.
- Create paths that cover every cell. Paths are continuous strips one cell wide.
- Form exactly eight paths whose lengths are 1, 2, 3, 4, 5, 6, 7, and 8. No other lengths are allowed, and each length appears once.
- For lengths 2 through 8, link one X to one O. The length equals the number of cells in the path, including both endpoints.
- For length 1, simply mark a solitary X. That cell stands alone as the monomino.
- Draw paths by dragging from an empty cell or an existing endpoint. Click a path segment to break it. Drag one endpoint onto another to merge paths.
- Continue until the grid is completely filled and the eight required lengths are present. A successful board shows no empty cells and satisfies every rule.
Core constraints that define a valid solution
Paths must remain simple strips. They cannot form a 2x2 solid block of filled cells. That configuration is called a pool and is forbidden.
A path also cannot touch itself along an edge. Diagonal contact is permitted, but sharing a full side with another part of the same path is not. Paths stay inside the 6x6 boundary and never overlap.
These restrictions turn the placement of the eight unique lengths into a deduction puzzle rather than free drawing. The fixed Xs and Os act as the only allowed endpoints (except for the length-1 X). Every other cell becomes part of exactly one path.
Practical approach to solving
Start by identifying forced short paths. An X that has no adjacent empty cells or reachable O must be the length-1 path. An X that can reach only one nearby O often forces a length-2 path.
Once short lengths are claimed, longer paths become constrained by the remaining space and the remaining open endpoints. Track the unused lengths so that a potential connection of length 5 is not attempted after the length-5 slot is already filled.
Watch for cells that would be isolated or forced into an illegal self-touch if a certain route is chosen. Corners and edges frequently dictate the direction of a path because the alternative would leave an endpoint stranded.
When two candidate routes look possible, test which one leaves the correct remaining lengths for the unsolved endpoints. The parity of the grid distance between an X and an O can also eliminate impossible matches: the number of cells in a path must match the available steps.
Interface features and progress tracking
The site offers multiple levels, a statistics panel that records solved counts, best times, average times, and a time-distribution breakdown, a global leaderboard ranked by solves and speed categories, and a puzzle archive that lists past boards with personal and community times.
A profile section allows guest play or saved progress. After solving, the interface displays the time taken, the number of moves, and the order in which paths were completed. Results can be shared, and the solved board can be reviewed.
These tools support both casual practice and competitive comparison without altering the core rules of the puzzle itself.