Common Patterns and Heuristics
High-signal cues that speed up your reads and avoid dead-ends.
Forced corners and edges
Near borders, the path often has only one legal continuation. Commit early when alternatives would isolate cells.
Diagonal traps
Two diagonally adjacent filled cells can isolate the opposite pair if you close the rectangle too early. Leave an escape.
Islands and pockets
Track pocket sizes. Odd-sized pockets can be impossible to traverse depending on start/end parity.
Number reachability
From N to N+1, ensure a simple path exists after each commitment. If choices remove all routes, undo.
Corridor threading
In 1-cell-wide corridors, alternating entry/exit is often forced. Plan the sequence before drawing.