Epicycle Gallery
Draw with rotating circles
$4.99 · Designed for iPad. Not verified for macOS.
Watch any curve rebuild itself from rotating circles. Browse mathematical sketches or invent your own in Fourier Lab, Circle Composer, Freehand, and Paste Diagram.
Epicycle Gallery is a hands-on studio for Fourier series. Any closed drawing can be rebuilt as a chain of rotating circles — epicycles. Open a sketch and watch the mathematics draw.
See the series, not just the formula.
Each sketch splits the screen: rotating circles on top, the reconstructed path below. Play, pause, or restart a cycle. Open Epicycle Details to read every harmonic's radius, phase, and speed.
A gallery of original mathematics.
Simple Shapes covers hearts, roses, Lissajous figures, rolling-circle families, and other classic curves. Complex Shapes pushes the same idea into denser harmonic weaves, nested spirographs, and a constructed nautilus. Every curve in the gallery is original mathematics — no third-party characters or logos.
Four labs when you want to invent.
• Fourier Lab — retune harmonics, samples, and speed on any gallery curve
• Circle Composer — stack circles by hand and invent new patterns
• Freehand Fourier — draw a stroke and decompose it
• Paste Diagram — paste point lists or a high-contrast line image; contours are extracted on your device
Built to teach.
Help & About explains what an epicycle is, how the discrete Fourier transform produces the circles, and how to read the screen. Reduce Motion shows the finished reconstruction immediately.
Private by design.
No account. No ads. No tracking. Drawings, clipboard text, and pasted images never leave your iPhone or iPad.
Download Epicycle Gallery and watch rotating circles become a drawing.
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The developer, Joao Frasco, 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.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Joao Frasco
- Size
- 5 MB
- Category
- Education
- Compatibility
Requires iOS 26.0 or later.
- iPhone
Requires iOS 26.0 or later. - iPad
Requires iPadOS 26.0 or later. - Mac
Requires macOS 26.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 26.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © 2026 Joao Frasco
