JellyDazzle
An audio-reactive kaleidoscope for Apple Silicon. It listens to whatever is playing —
on your Mac, iPhone or iPad — and paints to it, never the same pattern, never the same colours.
🎉 Version 3.6.6 — four new fractals, and see the beat
- Four new fractals: a neon Mandelbrot drawn as glowing filaments, Nova spiral basins, a
Multibrot that blooms from one fold to five and back, and Clifford attractors woven like silk.
- See the beat: a new M button puts the beat meter on screen — the bar is now
C · S · M · ? (colour, shape, meter, about).
- Every background drifts — some used to sit frozen at a random zoom — and the same kind of
shape no longer comes straight back.
- All 666 routines play, and 60+ patterns that looked identical each time now vary.
3.6.6 is the current release; all earlier versions are deprecated. It is on the
App Store for Mac,
iPhone and iPad — released October 13, 2026 — and the direct Mac download
below is 3.6.6.
An homage to DAZZLE.EXE, rebuilt from scratch — mostly C, with an ARM64 assembly core:
24 engine modes hand-written in ARM64 assembly under a library of 642 C pattern plug-ins,
layered by a compositor written in C.
⬇️ Download
Free, and it updates itself.
Not using the App Store? Signed, notarised direct download — always the latest version:
Download JellyDazzle for macOS · Apple Silicon (.zip)
- Unzip.
- Drag JellyDazzle.app into Applications.
- Open it. That is the whole install.
Code-signed as Developer ID Application: LIBCSYSTEMS LLC and notarised by Apple,
with the ticket stapled so it verifies offline. No "cannot verify" dialog, no right-click
trick — download it and open it.
macOS 11 or later · Apple Silicon (M1+) · MIT
Which one do I want? The App Store is for Mac, iPhone and iPad and updates itself
The direct download above is 3.6.6 for the Mac, signed and
notarised, for Macs that do not use the App Store.
⚠️ First launch can take 30–60 seconds while it measures the routine library and
probes audio devices. It is working, not hung. The measurements are cached, so every
later launch is immediate.
🔊 Play music first
JellyDazzle is audio-reactive — put something on before you watch it. Anything playing on
your Mac: a record, a film, a livestream. On macOS 14.2+ it listens to the system output, so
it follows whatever app is making the sound. In silence it still runs, but on internal clocks —
and you are seeing maybe half of what it does.
Nothing on hand? Play mine — And I Need Ur Love by
The Rat's Asses, featuring the guy who wrote this thing.
▶ Watch on YouTube — free, no account.
Also on Spotify, though free
accounts only get a 30-second preview there.
More at dazzle.jelia.nyc ·
browse every routine
iPhone and iPad
Version 3.6.6 is on the App Store now. It is the same engine — the
same ARM64 assembly core and all 666 routines — running
on iOS and iPadOS 15 or later.
- Your music keeps playing. iOS does not let one app hear another, so on a phone
JellyDazzle listens through the microphone. Spotify or Apple Music keeps playing at full
volume while it listens and paints.
- Lite on battery, Full when charging. On battery, in Low Power Mode, or when the device
is warm it draws a softer picture at 30 frames a second; plugged in it runs at 60 with every
layer. It switches on its own, mid-show.
- Buttons. C, S, M and ? sit in the corner for colours, shapes, the beat meter and help, brighten
when you touch the screen and fade while you watch. Tap = colours, two fingers = shapes,
press and hold = help, three fingers = a performance readout.
The iOS build (tools/build_ios.sh, with SDL patched in vendor/sdl2-ios) is in this repository.
What the built app contains
| |
|---|
| 24 | ARM64 assembly engine modes |
| 642 | C pattern plug-ins |
| 666 | routines total |
| 180 | palette schemes, interpolated in OKLab |
Every routine in the tree is compiled into the shipping binary. Nothing is held back.
The engine draws once and then moves the palette, the way the original did. Patterns are
scheduled into layers by how much they move on their own, so the stillest ones get the most
transform and nothing sits static. Two routines from the same shape family never share the
screen.
Controls
| key | |
|---|
| C | new colours. The whole palette cycles to a different scheme — not the next one, the one furthest from what is on screen. |
| S | new shapes. Every routine currently drawing is retired and the stack fills again from the library. Colour is left alone. |
| A · ? · H | help / about card — version, links, what is playing right now. Also Help ▸ JellyDazzle Help (⌘?) in the menu bar. |
| M | beat meter — bass, mid, treble, level and a dot that flashes on the beat |
| F | full screen |
| ESC | quit |
| buttons | C · S · M · ? in the bottom-right corner do the same with a click |
C and S split the show in two: one key changes what
it looks like, the other changes what it is doing. Either can be pressed at any time.
C picks at random inside the extreme band. It scores every scheme in the 180-strong
library against what is on screen, keeps the ones within 70% of the furthest, and chooses
among those — never repeating the scheme it just left. Taking the single furthest every time
looked right on paper but was deterministic, and colour distance is symmetric: from A the
furthest was B and from B the furthest was A again, so it toggled between two palettes and
the other 178 never appeared.
There is no F1 on macOS — the top row is display brightness — so help is on ⌘? from the
Help menu, alongside the A, ? and H keys.
Neither of them cuts. The engine has one law — nothing strobes — and a key press is not an
exemption from it: C crossfades to the new palette over two thirds of a second, and
S fades the old routines out under the same envelope that retires them normally. The
release gate measures this (gate keys): across seven starting seeds the worst
single-frame change after either press stayed inside the range the show already produces
on its own, and the whole cast turned over.
Audio
On macOS 14.2+ JellyDazzle taps the system audio output, so it moves with whatever is
already playing — Spotify, a browser, anything. On earlier versions it falls back to the
microphone, which is why macOS asks for permission on first launch.
Audio is turned into numbers and thrown away. It is analysed in memory to drive the current
frame and then discarded — never recorded, never stored, never transmitted. The app has no
network capability at all. Without permission the visuals simply run on internal clocks.
See the privacy policy.
Build it yourself
git clone https://github.com/LIBCSYS/JellyDazzle.git
cd JellyDazzle
make # build ./jellydazzle
make run # build and launch
make app # self-contained JellyDazzle.app
Needs only the Xcode command line tools (xcode-select --install).
SDL2 ships in this repository, built against the minimum supported macOS. That is
deliberate: a Homebrew SDL is compiled for whichever macOS the build machine happens to run
and silently pins the finished app to it — which is exactly what once made a public download
refuse to launch on anything but the newest system.
Layout
src/engine/ compositor.c scheduler + layer compositor
routines_asm.s 24 ARM64 assembly routines
jellydazzle.h the plug-in contract
src/audio/ listen.c bass / mid / treble / beat
systap.m Core Audio system-output tap
src/app/ main.c SDL window, native-resolution render loop
src/patterns/ NNN_name.c pattern plug-ins, named by what they draw
assets/ palette.bin, sintab.bin, palettes/ (sources)
packaging/ JellyDazzle.entitlements (App Store sandbox)
tools/ gen_palettes.py, gen_registry.sh, build_app.sh,
release_app.sh, build_appstore.sh
In tribute
JellyDazzle exists because of DAZZLE.EXE, written by James R. Shiflett of Houston,
Texas — at night, "a sort of therapy," as he called it. MicroTronics released it as shareware
in 1990. This is an homage, not affiliated with the original.
The full story.
Support
Questions, bugs, or anything else: [email protected] ·
support page
MIT licensed. Built by John Elia / LIBCSYSTEMS LLC.
