Rensa Lab
Daily chain-puzzle lessons
Free · In‑App Purchases · Designed for iPad. Not verified for macOS.
Miss a chain, and we show you what actually happened on the board: the group you cleared too early, where it stopped at 3, and where the trigger was.
Rensa Lab teaches chain puzzles — the kind where falling blocks clear in groups of four and set off chains — through a problem book. Place your pieces and see right away how many chains you made.
■ Explanations that tell you why
When you miss, we show what actually happened on the board: which group you cleared too early, where the falling blocks joined only a few and stopped, and where the trigger was. Replay the answer chain one step at a time.
■ 7 units, 210 problems
Basics → Find the trigger → Stair links → Sandwich links → Building 101 → Long chains → Advanced building. Start easy and work your way up.
■ Today's Problem
A new problem every day at midnight — easiest on Monday, hardest on Sunday. Home Screen and Lock Screen widgets show today's problem and open it in one tap.
■ Easy on the eyes
A paper-toned background, soft text color and large type. Every color has its own shape (triangle, diamond, square, hexagon), so you can read the board even if colors are hard to tell apart. Dark appearance is available in Settings.
■ Reminders only if you want them
We offer a reminder only after you solve your first problem. Turn it on and you get one reminder a day, at the time you choose.
■ No account, no ads, no server
Start right away without signing up. Your progress stays on this device, and explanations are made on your device without the internet.
■ How it works
Unit 1 (30 problems) and Today's Problem are included with no purchase. Units 2–7 (180 problems) unlock with a one-time purchase — not a subscription — which also includes every problem added later.
Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Privacy Policy: https://inphilchoi.github.io/chainlab-privacy/
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The developer, INPHIL CHOI, 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 Not Collected
The developer does not collect any data from this app.
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Information
- Seller
- INPHIL CHOI
- Size
- 20.1 MB
- Category
- Education
- Compatibility
Requires iOS 15.0 or later.
- iPhone
Requires iOS 15.0 or later. - iPad
Requires iPadOS 15.0 or later. - iPod touch
Requires iOS 15.0 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
English and 4 more
- English, Japanese, Korean, Simplified Chinese, Traditional Chinese
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Unlock All Problems $2.99
- Copyright
- © 2026 CreativeLab
