# The Fourth Dimension vs iRhythm Random

The clearest difference is update cadence: iRhythm Random at every 10 days against The Fourth Dimension's every 4 months. The Fourth Dimension's advantage is price ($2.99 vs $6.99) and iOS requirement (12.0 vs 17.0). On ads, in-app purchases and device support there is nothing between them.

The Fourth Dimension costs $2.99 and iRhythm Random $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

The Fourth Dimension ships an update every 4 months, iRhythm Random every 10 days. The most recent releases landed on October 16, 2026 and October 11, 2026 respectively.

## The numbers

| Metric | The Fourth Dimension | iRhythm Random |
| --- | --- | --- |
| Price | **$2.99** | $6.99 |
| Rating | **[4.8 (1.9K ratings)](https://appshunter.io/ios/app/the-fourth-dimension/id504201783/reviews)** | — |
| Number of ratings | **1.9K** | — |
| Positive reviews | 94.2% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 10 days** |
| Monetization | Free with in-app purchases | — |
| Size | 5 MB | 300 MB |
| Requires iOS | **12.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Lunar Skydiving LLC](https://appshunter.io/developer/504201786) | [Maurizio Salvi](https://appshunter.io/developer/1736599893) |

## What reviewers say

### The Fourth Dimension

[App page](https://appshunter.io/ios/app/the-fourth-dimension/id504201783)

Explore a complex mathematical concept through an interactive 3D experience. This app uses a unique touch interface to help you visualize and understand the fourth dimension in an engaging and accessible way.

**Highlights:** Interactive 3D touch interface, Explains the fourth dimension, Accessible language for all, 30-page interactive book, Visual and hands-on learning

**In-app purchases:** none


### iRhythm Random

[App page](https://appshunter.io/ios/app/irhythm-random/id6479618009)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is The Fourth Dimension free?

The Fourth Dimension costs $2.99, with no in-app purchases.

### Is iRhythm Random free?

iRhythm Random costs $6.99, with no in-app purchases.

### Do The Fourth Dimension or iRhythm Random have ads?

Neither The Fourth Dimension nor iRhythm Random shows ads.

### Which is updated more often, The Fourth Dimension or iRhythm Random?

The Fourth Dimension ships an update every 4 months, and iRhythm Random every 10 days. Most recently, The Fourth Dimension was updated on October 16, 2026 and iRhythm Random on October 11, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*