Chalk Star Lines

Six chalk dots, fifteen lines, one rule: close a triangle in your own colour and you lose - and a draw is mathematically impossible.

Chalk Star Lines is a quick abstract pencil-and-paper duel on a blackboard. You and your opponent take turns chalking one open line between dots in a ring. You draw pink, the opponent draws blue. Whoever completes a triangle in their own colour loses. Every line you add makes the board tighter, and sooner or later someone gets cornered.

HOW IT PLAYS
- Tap a faint line, or tap two dots, to chalk it in your colour.
- Dashed pink lines warn which open lines would close your own triangle.
- A live safe-line count shows who is closer to being cornered.
- Choose a ring of six, seven or eight dots.

THREE OPPONENTS
- Doodler: the gentlest opponent, good for learning.
- Scholar: a stronger, thinking opponent.
- Perfect: a flawless player on the six-dot ring. Can you find the only way to beat it?

WHY THERE IS NO DRAW
The Why tab holds an interactive proof. Flip any line and watch a one-colour triangle appear, then step through the six-dot walkthrough to see why every colouring of six dots hides a single-colour triangle.

FEATURES
- A quick two-player line duel on a ring of dots against a thinking opponent
- Dashed warnings and safe-line counts make the tactics easy to read
- Three opponents, including a flawless player on the six-dot ring
- Interactive explainer: flip any line and watch a one-colour triangle appear
- Stats, a How to play guide and awards to earn
- Fully offline, no ads, no sign-in - records and awards saved on device

Chalk Star Lines needs no internet connection, shows no ads and plays without sound, so it is easy to pick up anywhere. Haptics can be switched off in Options.