JellyDazzle
What it looks like
How a frame is built
Up to four layers run at once, bottom to top: a ground fills the screen, a field covers most of it with gaps, a figure drops distinct shapes over that, and a spark adds glints. They blend by brightness, so dark parts of an upper layer let the one below show through.
Each layer takes a turn of its own length, then a new routine is drawn from a shuffled bag and fades in. Timing is random by design — never a fixed loop. At startup the engine measures every routine and assigns it a layer by how much of the screen it actually covers.
Where things stand
A few people hit real problems with the earlier downloads. They are fixed, and it is worth being straight about what they were.
- It would not open on older Macs. The build inherited the macOS version of the machine that compiled it, so a copy built on the newest system simply refused to launch on anything earlier — which meant the download only worked for people already running the latest OS. The floor is now macOS 11, set explicitly and pinned in the bundled SDL2 as well, so what you download runs on hardware older than the machine that built it. Resolved in 2.7.
- It looked frozen when you first opened it. On first run JellyDazzle measures every routine in the library and probes the available audio devices before it draws anything, which on some Macs takes 30–60 seconds with nothing on screen. It was working, not hung. Those measurements are now cached and there is a count-up clock and a cancel, so it says what it is doing and every later launch is immediate. Resolved.
- Patterns repeated themselves. Two routines from the same shape family could end up on screen together, which made a library of hundreds feel smaller than it was. Families are now tracked and never share the screen. Resolved.
- macOS said it “cannot verify” the app. Fixed. Early downloads were signed only ad-hoc, so Gatekeeper could not check who made it and warned you. The current release is signed as Developer ID Application: LIBCSYSTEMS LLC and notarised by Apple, with the ticket stapled so it works offline. Download it, open it, done — no warning, no right-click trick.
Now on iPhone and iPad
The same engine — the same assembly core and all 666 routines — runs on iPhone and iPad. Version 3.6.6 — four new fractals, and see the beat — is on the App Store now, the same release as the Mac. Put a song on in Spotify or Apple Music, open JellyDazzle and set the phone down: your music keeps playing at full volume while JellyDazzle listens through the microphone and paints to it.
- Lite on battery, Full when charging. On battery, in Low Power Mode, or when the phone is warm it draws a softer picture at 30 frames a second; plug it in and it becomes full JellyDazzle — 60 frames, every layer. It switches on its own, mid-show.
- C, S, M and ? buttons in the corner for colours, shapes, the beat meter and help. They brighten when you touch the screen and fade while you watch. A tap gives new colours, two fingers new shapes, press and hold shows what is playing.
Your own pictures, the feature announced here before, is on hold — the phones came first. Get it on the App Store, or follow along at github.com/LIBCSYS/JellyDazzle.
Coming soon to Android
The same engine — the same assembly core and all 666 routines — is coming to Android phones and tablets. JellyDazzle for Android is with Google Play for review now. Like the iPhone, it listens to the music around it through the microphone, draws a softer picture on battery and goes full when you plug it in. Free, no ads, and it doesn’t even ask for internet access.
The Google Play button goes up here the day it is live.
What's new
- 3.6.6 — four new fractals, and see the beat. On the App Store for Mac, iPhone and iPad since Oct 13, 2026, and the direct Mac download is 3.6.6. 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. A new M button puts the beat meter on screen — the bar is now C · S · M · ?. Every background now drifts, the same kind of shape no longer comes straight back, and all 666 routines play.
- Earlier versions are deprecated. 3.6.6 carries everything they did — please update to it. The full history is in the source on GitHub.
Build it yourself
git clone https://github.com/LIBCSYS/JellyDazzle.git cd JellyDazzle make # build make run # build and launch make app # signed self-contained .app
Needs only the Xcode command line tools
(xcode-select --install). SDL2 ships in the repository, built against the
minimum supported macOS — deliberately, because a Homebrew SDL is compiled for whichever
macOS the build machine happens to run and silently pins the finished app to it. Apple Silicon
only; the 24 engine modes are hand-written ARM64 assembly (the 642 patterns and the compositor are C). macOS asks for microphone permission on
first launch so the visuals can move with your music — they run on internal clocks without
it. First launch can take 30–60 seconds while it probes audio devices; it is working,
not hung.
In tribute
JellyDazzle exists because of DAZZLE.EXE, written by James R. Shiflett of Houston, Texas. He wrote it at night — “a sort of therapy,” he called it — while his day job was administrative work around an NEC SX-2 supercomputer at the Houston Advanced Research Center.
MicroTronics released it as shareware in 1990 for $15. Road Scholar Software published it at retail as Razzle Dazzle in 1992, and by 1993 it was earning more in shareware registrations each week than most people made in a month. It went head to head with After Dark, and in 1993 its visuals became a 45-minute art film scored by Jonn Serrie.
Its source was never released. This is not a port and not a reverse engineering — nothing was disassembled. It is an homage written from scratch, chasing the same feeling: cheap geometry, mirrored symmetry, and colour that moves because the palette moves rather than because the pixels do.
Shiflett’s exit splash read:
“Our Creator, evidenced by our creativity.”