How to play Trail

Trail is a path puzzle: one line, every cell, numbers in order. Simple to learn, satisfying to plan. As always, no guessing is required — every board has a single solution.

The rules

• Draw one continuous line from number 1 onward.
• Pass through the numbered cells in order: 1, then 2, then 3, and so on.
• The line must fill every cell on the board exactly once.
• The line can't cross or revisit itself — it ends on the highest number.

Controls

• Press on 1 and drag to extend the line through neighboring cells.
• Drag backwards to undo a step.
• Tap any cell already on the line to rewind to that point.

Strategy

1. Mind the corners. A corner cell has only two neighbors, so the line must pass straight through it — that often fixes its two connections immediately.
2. Don't strand a cell. Every cell must be visited, so avoid moves that leave a cell with no way in or out. If a cell would become a dead end, route around it first.
3. Work the number segments. Between two consecutive numbers the line must cover a specific region of cells. Plan each segment so it doesn't block the next.
4. Fill from the edges in. Edges and corners have the fewest options, so committing them early narrows the interior choices.

Common mistakes

• Boxing yourself in. The usual way to get stuck is routing the line so a cell — or a whole pocket of cells — can no longer be reached. Before extending, glance ahead: will this move orphan a neighbour?
• Breaking the order. The line must reach the numbers in sequence (1, 2, 3 …), so the path between two numbers has to stay within the cells you can spare without blocking a later segment.
• Leaving a gap at the end. The line ends on the highest number and must have covered every cell exactly once. If a stray cell is left over, rewind and re-route an earlier segment rather than forcing the finish.

Why it clicks

Trail is a "one-line" (Hamiltonian-path) puzzle — part maze, part logic. Because every board has a single solution and fills every cell, solving feels less like drawing and more like proving the only route that works. It's quick to learn, endlessly replayable, and there's a Daily Challenge alongside unlimited random boards.

Frequently asked questions

Play Trail