Guess the Angle
Guess the Angle is a tiny geometry trainer. Every level draws a random angle between 10° and 350° and you have one job: figure out exactly how many degrees it measures. The rule is strict — you must hit the exact degree. No tolerance, no hints, no consolation scores. Simple, addictive, and surprisingly humbling — everyone thinks they know what 72° looks like until they have to name it to the degree.
How the game works
- Each level shows two rays from a common vertex. One is white (the reference ray, sitting at the level’s base orientation), the other is cyan (the target).
- Between them, a soft arc fills the angle you need to guess.
- Use the slider, the +/- buttons, or the keyboard arrows to set a value between 1° and 359°. Your guess is never drawn on the canvas — if it were, you could just align it with the target ray and read the answer. You’re on your own.
- Press Check (or Enter) to submit.
- Hit the exact degree → you pass, unlock the next level, and extend your streak.
- Miss by any amount → the same angle retries and the game tells you nothing about how close you were. No “off by 3°” breadcrumb to home in on.
Level progression
Handcrafted levels introduce the common angles first — 45°, 60°, 90°, 120°, 135° — so you build confidence with the familiar shapes. Later levels rotate the whole figure (so the reference is no longer conveniently horizontal) and mirror the angle direction (clockwise vs counter-clockwise) to stop you from memorising visual templates.
After the first tier, levels are endless. The generator cycles through tiers that:
- Tighten the target angle’s step from multiples of 5° → multiples of 2° → any integer from 10° to 350°.
- Randomize the base rotation and direction, so every level is fresh.
Because the match is exact, difficulty ramps up naturally: “multiples of 5” levels are already a real test, and the “any integer” tier is a full-on workout for your angular eye.
Tips to sharpen your eye
- Anchor on cardinals. 90° is a clean right angle; 45° bisects it; 30° is a third of 90°.
- Use the 180° reference. A straight line is 180°. If the two rays are almost opposite, you’re near 170°–190°.
- Divide mentally. Split the visible angle in halves to locate 45° and 90° sub-divisions inside it.
- Beware of rotation. The reference ray is not always horizontal; the game rotates it on purpose. Focus on the angular gap between the two rays, not their absolute positions.
- Commit to a single guess. Since the game doesn’t tell you how close you were, blindly nudging ±1° on retries doesn’t help. Reset your eye, re-estimate from scratch, and commit.
Keyboard shortcuts
←/↓: decrease by 1°→/↑: increase by 1°Enter: submit your guess
Why this game?
Angular estimation is one of those skills you think you have until you try to eyeball 73° in the wild. Forcing an exact match — with zero feedback on wrong tries — turns the training from “good enough” into “actually precise”. A couple of minutes a day and your intuition for geometry, CAD work, sketching, and even pool angles gets noticeably sharper.