Duotrace

Duotrace is a line puzzle with one rule: you trace every line in the shape exactly twice. A calm but thoughtful game, free in your browser.

About Duotrace

On screen sits a shape made of nodes joined by lines. You start at a node and follow the lines by moving to neighbouring nodes. The rule is single: each line has to be traced twice, not once.

It sounds simple, but things change as the shapes get tangled. Start from the wrong node and you end up one line short with no way back. So the game asks you to build the route in your head before you move.

Finishing a level gives a clear "got it" feeling. When you're stuck, pause, reset and a limited hint button are right there.

Why kids like this game

There's no time pressure and no losing screen. If it goes wrong you reset and try again, which makes patient thinking enjoyable.

Is this game safe for kids?

Yes. The screen holds only lines and nodes, with no violence, noise or anything uncomfortable. It runs in the browser and needs no account.

1. On a computer, left-click a node to start.
2. On phones and tablets, tap that same node.
3. Draw a line by picking the next connected node.
4. Try to trace every line exactly twice.
5. A line traced twice becomes marked.
6. If you get stuck, start over with the reset button.
7. The hint button gives a limited number of helps.

• Choose the starting node: most levels have only a few valid starts, so don't begin in the middle.
• Finish the corners early: ends with few connections close your route if left until last.
• Count what's done twice: following the marked lines makes the remaining ones easier to see.
• Watch for dead ends: entering a node with a single connection forces you back down the same line.
• Save the hint for last: uses are limited, so reset and try a different start first.

• Double-trace rule: every line is drawn exactly twice.
• One-tap control: picking the connected node is all you do.
• Calm pace: no time limit and no losing screen.
• Rising difficulty: shapes get more tangled as levels go on.
• Pause, reset, hint: three help buttons wherever you're stuck.
• Plays on any device with mouse and touch controls.