Math-based puzzlers tend to revolve around computation and sums, but Euclidea isn't like most games in that niche; rather than numbers, geometry is the focus, constructing figures and shapes with minimalist tools and within a minimalist aesthetic.
Euclidea starts out simple, easing you into its collection of geometric brainteasers by teaching how to create line segments, select points, draw circles. And then gradually, the challenge begins to increase, as you use intersecting circles to create equilateral triangles and perfectly bisect lines.
But the game isn't completely merciless. As you master the simpler tasks like deducing parallet lines, Euclidea provides tools that automatically perform certain actions. You'll need those tools, because while Euclidea may be easy to control, it certainly isn't an easy game. Figuring out to create a perfect hexagon within a circle or trisecting an angle requires you to think ahead, understand how points and intersections and line segments all interact and can be used together. Euclidea's puzzles are cumulative, building upon what you figured out before and challenging you to use that knowledge in new ways.
Euclidea is free to download on the App Store; a $0.99 in-app purchase unlocks the full game.