# KIKARAKU - Geometry Puzzles — Move shapes, feel the theorems

> Move shapes, feel the theorems (iPhone/iPad app by Fuji Bit Inc..)

- Source: https://appshunter.io/ios/app/kikaraku-geometry-puzzles/id6761917963 (this page in markdown: same URL + `.md`)
- Developer: [Fuji Bit Inc.](https://appshunter.io/developer/1874205957)
- Category: Education, Entertainment
- Price: Free
- Age rating: 4+
- Requires: iOS 13.0 · 23 MB
- Languages: Japanese
- Released: 2026-04-14
- Data updated: 2026-06-07
- User reviews in markdown: https://appshunter.io/ios/app/kikaraku-geometry-puzzles/id6761917963/reviews.md

## What is KIKARAKU?

Your intuition is about to be proven wrong, beautifully.

Geometry is full of properties that most people get wrong on instinct. KIKARAKU is an educational app that lets you experience 12 famous counterintuitive themes through four interactive phases: be surprised, verify it with your own hands, and understand why it works.

■ Four phases, from surprise to understanding

[Intuition Quiz]
Answer with your gut first. These are the questions most people get wrong.

[Hands-on Experience]
Move the shapes with a slider and watch the moment your intuition flips.

[Explanation]
Why is it true? Clear visual explanations that turn the basic theorems into the tools that resolve the surprise.

[Comprehension Check]
Confirm your understanding with another counterintuitive or applied problem.

■ 12 counterintuitive themes

- Angle Puzzle — a polygon's exterior angles always sum to 360 degrees
- Triangle Secrets — Napoleon's theorem (joining the centers always gives an equilateral triangle)
- Pythagoras — the vanishing square (a missing-square illusion)
- Tangram — the same area, yet a very different perimeter
- Area Master — the isoperimetric problem (for a fixed perimeter, the circle wins)
- Symmetry & Transform — the coin rotation paradox (two turns, not one)
- Circle Theorems — the rope around the Earth (about 16 cm, no matter the radius)
- Nets — spider and fly, the shortest path across a surface
- Similarity & Ratio — the square-cube law (twice as tall, eight times heavier)
- Golden Ratio & Beauty — the golden angle 137.5 degrees and densest packing
- Coordinate Geometry — taxicab geometry (where a circle becomes a square)
- Volume & Surface Area — Gabriel's horn (finite volume, infinite surface area)

■ Features
- Interactive, hands-on understanding
- Dark / light mode
- Japanese / English

Part of the "RAKU" educational series — the 11th installment.


## Version history (last 4 releases)

### 3.1 — 2026-06-02

- Improved screen transitions when clearing a stage, for greater stability.
- Minor usability improvements and bug fixes.

### 2.0 — 2026-05-29

Added two new stages, for a total of 12.

- Coordinate Geometry — explore distance, slope, and midpoint between two points on the coordinate plane
- Volume & Surface Area — explore the volume and surface area of solids such as cubes, cylinders, and spheres

We also improved the clarity of diagrams and overall usability, and fixed minor issues.

### 1.1 — 2026-04-29

We have fixed the bug.

### 1.0 — 2026-04-14

No release notes.

## More apps by Fuji Bit Inc.

- [SUUGAKU](https://appshunter.io/ios/app/suugaku/id6759102221)
- [BUTURAKU](https://appshunter.io/ios/app/buturaku/id6759213255)
- [PAKEDOU](https://appshunter.io/ios/app/pakedou/id6759820254)
- [OKURERUNA！](https://appshunter.io/ios/app/okureruna/id6759956971)
- [HARAKU](https://appshunter.io/ios/app/haraku/id6759958253)
- [KORAKU](https://appshunter.io/ios/app/koraku/id6760215571)

All apps by Fuji Bit Inc.: https://appshunter.io/developer/1874205957

## Related topics

[円楽](https://appshunter.io/ios/topics/)

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*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 2026-06-07.*