Two simulated chemicals feed and consume each other underneath a terminal grid, and the slowly creeping coral, spots and mazes they form show only through characters of rising density.
Two simulated chemicals feed and consume each other underneath a terminal grid, and the slowly creeping coral, spots and mazes they form show only through characters of rising density.
In the app you can adjust the colours, pattern and columns. It runs natively on your Mac, drawn live in real time – no video, never quite the same twice.
Use it on your Mac
- Get SCRNSVRS free from the Mac App Store.
- Select ASCII Reaction in the library.
- Click Set as Screensaver or Set as Wallpaper – or both.
Preview free · macOS Tahoe 26 or laterNeed a hand? Read the setup guide.
ASCII Reaction FAQ
How do I set ASCII Reaction as my screensaver on a Mac?
Install SCRNSVRS free from the Mac App Store, select ASCII Reaction in the library and click Set as Screensaver. macOS starts it whenever your Mac is idle, exactly like a built-in screensaver.
Can I use ASCII Reaction as a live wallpaper?
Yes. Click Set as Wallpaper in SCRNSVRS and ASCII Reaction plays on your desktop behind your windows and icons. You can use it as screensaver and wallpaper at the same time.
Is ASCII Reaction free?
ASCII Reaction is included in SCRNSVRS Unlimited. It's free for your first 7 days; after that Unlimited is $1.99/month or $9.99/year (€1.99/month or €9.99/year) for every screensaver, including new ones. It can also come up in Free this month, when 25 premium screensavers are free for everyone.
Is ASCII Reaction a video loop?
No. ASCII Reaction is rendered live on your Mac with Metal, so it never repeats and stays sharp on any display size. The clip on this page is a screen recording of the real thing.
Will ASCII Reaction slow down my Mac or drain the battery?
No. SCRNSVRS drops to 30 fps on battery and stops rendering when the wallpaper is covered by a full-screen app, so ASCII Reaction costs next to nothing in everyday use.
Which Macs does ASCII Reaction run on?
ASCII Reaction needs macOS Tahoe 26 or later.
