Euler's Circuit - One Line
Relaxing logic & brain puzzle
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Straight runs trace themselves — you only ever choose at a fork. Five circuits per set, about three minutes a session, and a dead end costs you nothing.
Trace every wire in a single stroke, and light up the circuit.
Euler's Circuit is a quiet one-stroke (Eulerian circuit) puzzle. Tap or drag from node to node to trace the wires. Wherever there is only one way forward, the current runs on its own — the only thing you ever decide is which way to go at a fork.
Designed not to tire you out
- Straight runs auto-advance, so you only act where a real choice exists
- Dead ends carry no penalty — you simply rewind to the last fork you chose
- No lives, no game over, no timers
- One set is five circuits: a complete session in about three minutes
Clean solutions, not high scores
- Three stars per circuit: finish it, finish without a dead end, finish without a hint
- "Elegance" multiplies the wire count by Euler's number e (2.718…) for a flawless solve, or √e if you used a hint
- New sets open as you complete them, growing larger and branchier
- Daily Challenge: the same five circuits for everyone in the world, with a streak calendar
- Game Center leaderboards for total stars and today's elegance
The mathematics is the game
Every circuit is generated so that each node has an even number of wires — by Euler's theorem, a solution always exists. A dead end only means your route stranded an island of wires behind you.
The title spiral is an Euler spiral (clothoid). Background particles orbit the unit circle of e^(iθ), colors step around the hue wheel by 1/e, and the soundtrack is synthesized in real time using just intonation (1 : 9/8 : 5/4 : 3/2 : 5/3), with melodies walking the scale in the digits of e.
Ads appear only between sets — never while you are tracing — and never in the Daily Challenge. The one-time Premium purchase removes them entirely.
Ratings & Reviews
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We’ve updated the App Store information.
The developer, Kenichi Horiuchi, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Used to Track You
The following data may be used to track you across apps and websites owned by other companies:
- Identifiers
Data Not Linked to You
The following data may be collected but it is not linked to your identity:
- Identifiers
- Usage Data
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Kenichi Horiuchi
- Size
- 11.7 MB
- Category
- Puzzle
- Compatibility
Requires iOS 26.0 or later.
- iPhone
Requires iOS 26.0 or later. - iPad
Requires iPadOS 26.0 or later. - Mac
Requires macOS 26.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 26.0 or later.
- iPhone
- Languages
- English and Japanese
- Age Rating
4+
- 4+
- Contains
Advertising
- In-App Purchases
Yes
- Premium $3.99
- Copyright
- © Kenichi Horiuchi
