OneTrail: One Line Draw Puzzle

Draw the whole figure in one continuous line. Never lift your finger, never trace the same line twice.

OneTrail generates every board on your device, and verifies that a solution exists before showing it to you. You will never be handed an impossible puzzle.

■ Five ways to play

· Journey - 8 worlds x 30 stages (240 boards): grid, diagonal, triangular, radial, mandala and web. Seeded, so stage 4-12 is the same board on every device.
· Daily puzzle - one board a day for the whole world. The shape and difficulty change with the weekday, and a calendar tracks your streak.
· Endless - choose the shape, the size, the difficulty, and whether the trail has to return to where it started. A fresh board every time.
· 60-second Rush - how many can you clear in a minute? They grow as you go.
· Gallery - 26 classic figures designed by hand and verified one by one: the envelope, Santa's house, the bridges of Koenigsberg, the Star of David, a snowflake, a gear wheel and more.

■ Difficulty that matches how it feels

Difficulty is not measured by counting lines. It is measured by how likely a player drawing at random is to finish in one go. The more branching traps a board hides, the lower that number - which is exactly what makes a puzzle feel hard.

■ Hints that never lie

A hint does not simply point at a line. It works out whether the lines you have left can still be finished, and if you are already stuck it rewinds you to the last moment the puzzle was still alive. You can also ask the game to stop you from making a fatal move at all.

■ Made to be quiet

· Fully offline - it works from start to finish in airplane mode
· No account, no login. Every record stays on this device
· No location, camera, microphone or storage permission
· Ads never gate the game. Hints are a bonus, and when no ad is available we simply grant them anyway
· Light and dark theme, left-handed layout, adjustable line thickness

■ Records that add up

Best times, total clears, lines drawn, undo and hint usage, daily streaks and achievements. Back up and restore everything by copying a single string.

Languages: English, Korean, Japanese, Chinese, Spanish, Portuguese, French, German, Russian, Indonesian.