Connect matching nodes across the topological grid.
Solve the built-in campaign levels.
Design, customize, and save your own grids.
Manage, share, and track your solutions.
Publish grids, unlock invite-only groups, and test community creations.
Design custom paths for different tile geometries.
Explore the combinatorics and topology behind easy, hard, and impossible grids.
Continue the campaign, or generate a fresh board with your chosen geometry and difficulty.
Play the built-in curated levels exactly as before.
Use the default tiles for a generated board. Choose the geometry, layers, pairs, and difficulty from a dedicated random panel in the game view.
A mathematical lens on size, structure, solvability, and why local tile rules transform global difficulty.
Core idea
Size alone does not determine difficulty. A larger board can be easier if it creates more routing slack, more alternate corridors, or fewer forced collisions. A smaller board can be brutal when a handful of local choices controls the entire network.
In other words, hardness often comes from structure, not scale: bottlenecks, endpoint ordering, symmetry, local rigidity, and how much freedom each tile preserves for the rest of the puzzle.
Before asking for the best route, ask whether any valid route exists at all. Boundary placement, disconnected regions, narrow bottlenecks, and forced pairings can make a puzzle impossible before the search truly begins.
Some grids collapse to a single rigid routing. Others admit many valid completions. Counting solutions tells us how constrained a puzzle really is, and whether the challenge comes from logic, exploration, or ambiguity.
Among all valid routings, which one is the cleanest? Simplicity might mean fewer turns, fewer detours, more symmetry, or more natural pairings. The simplest solution is not always the one that is easiest to discover.
The key issue is flexibility. A two-path tile makes each placement a strong commitment, and those commitments propagate across the board. A three-path tile changes the global behavior because it introduces more slack, more rerouting options, and fewer brittle dead ends.
Manage grids, retrieve saved progress, and view solutions.
localStorage.Publish your own grids, unlock private invite-code groups, and test what the community is building.
Choose one of your saved Repository grids, bundle any custom tiles it depends on, and share it with the wider community or an invite-only group.
Add any invite codes people have shared with you. Matching community cards will appear alongside the public ones and stay saved on this device.
No invite codes saved yet. Public community cards will still appear below.
All paths perfectly routed.
Configure grid → drag letters to boundaries → save to repository
Design custom routing logic for any geometry.
Drag tiles onto 🗑️ to delete them permanently.