Spiral Letter vs Two Links Double Pendulum
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Spiral Letter
Create visually striking messages by arranging text in a spiral. Customize sentence orientation, rotation direction, and even individual character colors for maximum impact. Express your thoughts with unique flair.
- Spiral text arrangement
- Customizable sentence orientation
- Adjustable rotation direction
- Individual character font color setting
- Add impact to messages
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You can arrange your message in a spiral and express it with great impact. This app can change the orientation of the sentense and direction of rotation etc. New features Font color can be set for each character.
Two Links Double Pendulum
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Two Links brings one of physics' most beautiful chaotic systems to life. Watch a double pendulum swing, twist, and spiral in real-time 3D — then place it on your floor in Augmented Reality and walk around it. Features • Real-time double pendulum physics (RK4 integration) • AR mode — anchor the pendulum on any flat surface • Orbit the 3D scene freely or let it run hands-free • Adjust link length, pivot position, density, and color • Particle trail from the second link tip • Night sky environment with the Moon and Earth • Pause, shuffle, and watch the chaos reset
Screenshots
Verdict
The clearest difference is ads: Two Links Double Pendulum at none against Spiral Letter's shown. Spiral Letter's advantage is iOS requirement (10.3 vs 18.2). On price, update cadence, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Spiral Letter ships an update every 54 months, Two Links Double Pendulum every 47 months. The most recent releases landed on October 16, 2026 and October 25, 2026 respectively.
| Parameter | Spiral Letter | Two Links Double Pendulum |
|---|---|---|
| Price | Free | Free |
| Rating | 3.0 (1 ratings) — better | — |
| Positive reviews | 0.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 54 months | Every 47 months — better |
| Ads | Yes | No — better |
| In-app purchases | No | No |
| Monetization | Ad-supported | — |
| Devices | iPhone, iPod | iPhone, iPad |
| Requires iOS | 10.3 — better | 18.2 |
| Further details — not scored | ||
| Size | 50 MB | 281 MB |
| Age rating | 4+ | 4+ |
| Developer | EIICHI KOMINE | Eliott Radcliffe |
In-app purchases
Spiral Letter
No in-app purchases
Two Links Double Pendulum
No in-app purchases
Questions
Is Spiral Letter free?
Is Two Links Double Pendulum free?
Do Spiral Letter or Two Links Double Pendulum have ads?
Which is updated more often, Spiral Letter or Two Links Double Pendulum?
Other comparisons
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