a puzzle game of light, arranged.
Place mirrors. Rotate prisms. Watch rays trace themselves.
No submit button. The field knows when you’ve solved it.
the concept
Light obeys.
You arrange.
Eikonal is built on a real ray-tracing simulation. Every frame, light leaves the source and resolves against whatever you’ve placed — mirrors reflect, prisms disperse, filters absorb, splitters branch.
There is no “submit.” The puzzle recognizes itself solved when the ray field satisfies every required receiver. Nudge a mirror by a degree, and the solution either falls into place or it doesn’t.
Named for the eikonal equation — the high-frequency limit of Maxwell’s equations that describes how light bends through changing media.
the spectrum
Three wavelengths.
One composite white.
Eikonal uses a discrete spectral model. A prism splits white into its three components; a filter rejects all but one. Color isn’t decoration — it’s state.
- red700 nm
- green546 nm
- blue436 nm
- whiter + g + b
the elements
A small kit. Deep combinations.
- Flat mirrorReflects the incident ray. Rotate to aim.
- PrismDisperses white into red, green, blue.
- FilterTransmits one wavelength. Absorbs the rest.
- Beam splitterTwo children from one parent ray.
- SourceEmits a single colored ray.
- ReceiverAccepts a ray of a specified color.
More on the way: convex and concave lenses, fiber channels, diffraction gratings, caustic reflectors.
the loop
Four steps. No prompts.
- 01PlaceDrop elements onto the field from the tray.
- 02RotateTwo-finger twist, or drag the handle.
- 03ObserveThe simulation runs continuously. Rays show truth.
- 04SolveWhen every required receiver lights up — you’re done.
the details
Built right, kept small.
- Native iOS 17+SwiftUI shell, SpriteKit scene. Pixel-true on every device.
- iPhone & iPadPortrait on phone; full orientation on iPad.
- Real ray tracingProtocol-driven engine. No baked-in solutions.
- 120 Hz safeDirty-flag simulator. Smooth even on ProMotion.
- No adsEver. Not in the binary.
- No trackingNo analytics SDKs. No telemetry phoning home.
- No IAPOne price. Every level.
- OfflinePlays on a plane. Plays in a tunnel.
- AccessibleVoiceOver-aware receivers. Dynamic Type honored.
- QuietNo timers. No streaks. No nags.
Bend a few rays.
Eikonal is available on the App Store.
Open in App StoreRequires iOS 17 or later. Universal binary.