# Euler's Circuit — One-stroke logic puzzle

> One-stroke logic puzzle (iPhone/iPad app by Kenichi Horiuchi.)

- Source: https://appshunter.io/ios/app/eulers-circuit/id6792647040 (this page in markdown: same URL + `.md`)
- Developer: [Kenichi Horiuchi](https://appshunter.io/developer/1553401480)
- Category: Games, Board, Puzzle
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 26.0 · 11 MB
- Languages: American English, Japanese
- Released: 2026-08-13
- Data updated: 2026-08-22
- User reviews in markdown: https://appshunter.io/ios/app/eulers-circuit/id6792647040/reviews.md

## What is Euler's Circuit?

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.

## Pricing and in-app purchases

Base price: Free.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Premium | $3.99 | one-time |



## Version history (last 1 release)

### 1.0 — 2026-08-13

No release notes.

## More apps by Kenichi Horiuchi

- [Shadow Runner 3D](https://appshunter.io/ios/app/shadow-runner-3d/id1553401478)
- [RePlayCamera](https://appshunter.io/ios/app/replaycamera/id1658772020)
- [EasyHealth Track](https://appshunter.io/ios/app/easyhealth-track/id6450302663)
- [Auto Mirror](https://appshunter.io/ios/app/auto-mirror/id6740739536)
- [Fermat's Math Puzzle](https://appshunter.io/ios/app/fermats-math-puzzle/id6788619489)

All apps by Kenichi Horiuchi: https://appshunter.io/developer/1553401480

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-22.*