Euclidea: Geometry Puzzles

Can you build a right angle in just three moves? The goal looks simple. Finding the way there is the puzzle.

Euclidea is a logic puzzle game built around lines, circles, and surprisingly short solutions. Your two basic tools are a straightedge—a ruler without markings—for drawing lines, and a compass for drawing circles. A few moves can take you a long way, once you find out which ones.

Start with curiosity

The first puzzles introduce the tools through play. You can begin without knowing a theorem for every problem, and if a definition slips your mind, the glossary is there.

You don't need a steady hand, either. Lines stay straight, circles stay round, and points have a certain pull: snapping helps you place lines and circles where you want them. You supply the ideas.

Find your own way

Try an approach, undo a step, or start again. There is no single intended sequence to guess. Euclidea checks the figure you build, so an unexpected route counts just as much as the textbook one. There are no timers, no lives, and no ads.

Then comes another challenge: can you do it in fewer moves? Earn stars by meeting the move-count goals. A method you already know may get you to the answer, but a tighter limit can send you looking for a completely different idea. Even a solved puzzle can have another surprise waiting.

Live constructions

Everything you build is live. Drag points and watch lines and circles move together, revealing relationships that a still drawing can hide. Euclid and the ancient Greeks worked with the same two tools. Their drawings never moved.

Not sure what you need to construct? Switch to Explore mode to see the target figure. Move the starting points to see how it behaves, and watch how your own construction moves in relation to it. Then build it yourself. Hints are there if you get stuck.

Discover why it works

You may find a solution before you understand why it works. Why do those lines stay at right angles when you move a point? A puzzle you have solved can give you a reason to learn the geometry behind it.

Use logic, imagination, and spatial reasoning as you explore. Even if geometry at school never appealed to you, working out a solution for yourself can feel very different.

What's inside

- 148 geometry puzzles in 15 packs, plus 8 tutorial levels

- Challenges ranging from simple first steps to demanding brain teasers with tight move limits

- 10 tools that unlock as you progress

- Live constructions, Explore mode, and hints when you need help

- A glossary for checking geometric definitions

- Zoom and pan to take a closer look

The first two packs, with 23 levels, are free. A one-time purchase gives you access to all packs. Prefer to earn your way? Collect every star as you go and the next pack opens, all the way to the end.

Questions or feedback? Visit https://www.euclidea.xyz/

Happy solving!