Trail (Puzzle Round)

About Trail (Puzzle Round)

Trail is a path puzzle built on the Hamiltonian path, a route that visits every point exactly once; Puzzle Round has an article on its history. The grid has numbered cells from 1 to 10 scattered across it.

You draw a single line that starts on 1 and ends on 10. It must pass through the numbers in order and cover every cell of the grid exactly once, with no gaps and no crossings. Tapping or dragging into a neighbouring cell extends the line, and tapping a cell already on the path rewinds it to that point, so trying an idea costs nothing.

Players of LinkedIn's Zip will recognise the format. Trail tends to be one of the faster games in the lineup, and the timer and leaderboard make the race part of the fun.

Puzzle Round is a free website of short daily puzzles by thatsoftwaredude, an independent developer. Every player gets the same puzzles each day, a countdown on the site runs to the next midnight UTC, and each game keeps its own daily leaderboard ranked by solve time. You can play without signing up; a free account saves your result to the leaderboard and keeps your streak, and private Circles let a family or a group of friends compare results. Clearing the whole lineup in a day counts as a Perfect Day.

How to play Trail (Puzzle Round)

1. Open puzzleround.com/trail to load today's grid.
2. Start on 1 and tap or drag into a neighbouring cell to extend the path.
3. Pass through the numbers in order, 1 to 10.
4. Cover every cell exactly once; tap the path to rewind if you get stuck.
5. End on 10 with the grid full to stop the clock.

Tips

• Corners and edge cells are easy to strand: plan how the path reaches them.
• Look at the stretch between two consecutive numbers and count the cells it must use.
• A cell with only two open neighbours fixes the path through it.
• Rewind early rather than finishing a route that leaves an isolated pocket.

Questions