# Rondo – Prime Factorization — Watch numbers dance & sing > Interactive prime factorization visualization and auditory exploration app. (iPhone/iPad app by KEN TOMINAGA.) - Source: https://appshunter.io/ios/app/rondo-prime-factorization/id6784029039 (this page in markdown: same URL + `.md`) - Developer: [KEN TOMINAGA](https://appshunter.io/developer/975026926) - Category: Education, Entertainment - Price: Free with in-app purchases - Rating: 5.00/5 from 1 App Store ratings - Age rating: 4+ - Requires: iOS 26.0 · 8 MB - Languages: American English - Released: 2026-06-29 - Data updated: 2026-08-11 - Monetization: free with in-app purchases - User reviews in markdown: https://appshunter.io/ios/app/rondo-prime-factorization/id6784029039/reviews.md ## What is Rondo? Rondo turns the counting numbers into a quiet, hypnotic dance. Every number from 1 upward is drawn as a factorization diagram: nested rings of colored dots that show, at a glance, how that number is built from its prime factors. 6 is two groups of three. 12 is three groups of four. Primes can't be split, so they shimmer alone. Then the diagram melts and re-forms into the next number, and the next, an endless looping dance of arithmetic. It's equal parts math toy, teaching tool, and ambient art. WATCH, OR EXPLORE • Let it play for a calm, continuous dance from one number to the next • Tap to pause, drag to scrub to any number, or step one at a time • Speed it up, or slow it right down • A gentle haptic tap each time the dance lands on a prime HEAR IT • Every number sings its factorization: a prime is a single pure tone, a composite a chord of its prime factors • On by default, off whenever you like POINT YOUR CAMERA • Aim Rondo at any printed number and watch its diagram bloom over the page, in augmented reality • Lift a number's diagram off the page and into the room, then walk around it • Street signs, receipts, book pages: factor the world around you EVERY NUMBER HAS A STORY • Tap any number to see what makes it special: whether it's prime, a perfect number, a power, and more • Collect the special numbers you find in the Field Guide SEE THE MATH • The current number and its factorization, always in view • Full VoiceOver support and a spoken read-out of each number and how it factors • Save the numbers you love to Favorites, and share any diagram as an image ON YOUR HOME SCREEN AND WRIST • Widgets that turn today's date into factorization diagrams, across the Home Screen, Lock Screen, and StandBy • A factorization calendar for the month or the current week • An Apple Watch app: scrub through the numbers with the Digital Crown, with the same prime haptics MAKE IT YOURS WITH RONDO PRO A one-time unlock, never a subscription. The full dance stays free. Pro is for going deeper: • New color palettes, backgrounds, and color styles • A living clock face that factors the time • Number sequences: count by multiples, primes only, Fibonacci, and more • The full instrument: tune the scale, voice, and space of the sound • Hear any number's story narrated aloud, in your choice of tone CALM BY DESIGN No ads. No tracking. No account. No subscription. Rondo is free to play, with an optional one-time Pro unlock. A LOVING HOMAGE Rondo is a faithful tribute to Brent Yorgey's factorization diagrams and Stephen Von Worley's animated "Factor Conga," built natively for iOS 26. The diagrams honor their work; the sound, the augmented reality, and the stories are Rondo's own. Full credits are in the app. ## Key features - Animated factorization diagrams - Augmented reality number visualization - Auditory representation of factors - Interactive number exploration - Field Guide for special numbers - Home screen and Apple Watch widgets - Customizable color palettes and sounds ## Pricing and in-app purchases Base price: Free. **One-time purchases** | Purchase | Price | Type | | --- | --- | --- | | Tip a prime · 199 | $1.99 | one-time | | Tip a prime · 499 | $4.99 | one-time | | Tip a prime · 599 | $5.99 | one-time | | Tip a prime · 1999 | $19.99 | one-time | | Rondo Pro | $4.99 | one-time | ## Frequently asked questions about Rondo ### What is Rondo? Rondo is an educational app that visualizes numbers as prime factorization diagrams, allowing users to watch, hear, and explore their mathematical structure. It functions as a math toy, teaching tool, and ambient art experience. ### How does Rondo teach prime factorization? Rondo displays each number as nested rings of colored dots representing its prime factors. Users can interact with these diagrams, pause the animation, scrub through numbers, and even see the factorization in augmented reality. ### Can I use Rondo without an internet connection? The core functionality of Rondo, including watching and exploring factorization diagrams, is available offline. Augmented reality features may require an internet connection for initial processing or specific AR capabilities. ### What devices does Rondo support? Rondo is designed for iPhone, iPad, and Apple Watch, offering a consistent experience across Apple devices. Widgets are also available for Home Screen, Lock Screen, and StandBy. ### Does Rondo have ads? No, Rondo is designed to be calm and free from distractions. It does not contain advertisements, tracking, or require an account. ### What features are included in Rondo Pro? Rondo Pro is a one-time unlock that offers new color palettes, backgrounds, a living clock face, number sequences (multiples, primes, Fibonacci), advanced sound customization, and narrated number stories. ### How often is Rondo updated? Rondo was last updated on July 2, 2026, to version 1.1.0. Updates typically include new features, performance improvements, and bug fixes to enhance the user experience. ### What is the age rating for Rondo? Rondo has an age rating of 4+, making it suitable for young learners and individuals of all ages interested in mathematics. It features full VoiceOver support for accessibility. ## Version history (last 5 releases) ### 1.2.4 — 2026-08-08 Bug fixes and improvements. No ads, no tracking, no account, ever. Thanks for dancing with us. ### 1.2.3 — 2026-08-06 Behind-the-scenes tidying, plus a few small fixes. No ads, no tracking, no account, ever. Thanks for dancing with us. ### 1.2.2 — 2026-07-27 Small fixes and quiet improvements under the hood. No ads, no tracking, no account, ever. Thanks for dancing with us. ### 1.2.1 — 2026-07-22 Small fixes and quiet improvements under the hood. No ads, no tracking, no account, ever. Thanks for dancing with us. ### 1.2.0 — 2026-07-20 The numbers now take you places. • Collatz Orbit: pick a number and ride its journey all the way down to 1, with a supernova when it soars past what dots can draw. Start it from Settings. • Fluid scrub: flick the dance and it coasts with real momentum, buzzing through the primes as it slows. • Special-number days: opt in to a gentle heads-up when the day of the year is itself a special number, like day 233. • Plus a small maker's mark on shared cards and quiet improvements under the hood. No ads, no tracking, no account, ever. Thanks for dancing with us. ## More apps by KEN TOMINAGA - [Swifter - Get the latest news, for Swift -](https://appshunter.io/ios/app/swifter-get-the-latest-news-for-swift/id975026927) - [Coppie as markdown](https://appshunter.io/ios/app/coppie-as-markdown/id1297207273) - [Count and Speak](https://appshunter.io/ios/app/count-and-speak/id1300251161) - [BrewSmart: Coffee Ratio](https://appshunter.io/ios/app/brewsmart-coffee-ratio/id6745852921) - [LinkClean – URL Cleaner](https://appshunter.io/ios/app/linkclean-url-cleaner/id6758604043) - [Whyzard – Learn Together](https://appshunter.io/ios/app/whyzard-learn-together/id6766441698) All apps by KEN TOMINAGA: https://appshunter.io/developer/975026926 --- *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 2026-08-11.*