I ended up writing the After Dark 3.0 engine for Mac, which was a lot of fun because I wrote it as an application and then figured out how to make it run within the context of the frontmost application without affecting it. It only patched 5 system traps rather than the 20+ traps the previous engine patched.
We were in constant competition with an Apple Engineer named Tom Dowdy that had a freeware product "Dark Side of the Mac" that patched no traps at all - patching was always blamed for system instability.
It seems like so much work went into something really small... I remember countless overnights, costo runs, alcohol, and a dead hamster named Trurl.
I don't remember where I got this idea but I coded up a screensaver very quickly once. The idea was it periodically would make a 1/2 x 1/2 size copy of the screen and then copy it to the bottom right, bottom left and top center of the screen. This converges on a fixpoint called the Serpinski Gasket. On Windows it was pretty easy to write such screen savers. I'd be interested in doing it under X Windows but the people who maintain X Windows (or DEs) are not interested in maintaining end-user-facing variety in screen savers. And if you can do it it means that rogue software can exfiltrate image captures of your running programs.
I also want to quickly mention PointCast  as an example of another current in the screensaver sea.
Probably. A deeper answer would be off-topic, in my judgement.
Operating Systems also came with their own screen savers plus the people that liked screen savers were not prone to buying software, usually software was pirated or unlicensed in the 90s. Therefore this crowd were happy with openGL Windows screen savers. This was during a time when the Mac barely existed in the corporate world.
Really this product should never have existed and we should have moved to modern power management of monitors 30 years ago. Think of the electricity that could have been saved.
The first CRTs were actually used as memory and the fact that the phosphor 'remembered' what it had shown was an engineered thing. Then CRTs were used as displays that you could 'burn in' the contents was a problem .
That started the notion of not keeping the same thing on the screen all of the time which was "hard" to do for character driven terminal screens, but possible with bitmap driven screens. The first 'screen saver' I saw was at PARC on an Alto of all things which was drawing lissajous figures during idle time. They also appeared in arcades where screen burn was an issue so the game would display something else to avoid screen burn.
And THEN the energy crisis hit and everyone was looking at saving energy so CRT manufacturers added a simple circuit that if you disabled vertical sync they would detect that and actually turn off the electron beam completely. (horizontal sync was still needed to maintain the high voltage field at the front of the CRT). But by now a lot of people had grown attached to screen savers so turning off the screen was avoided.
And then we got to LCDs where running a screen saver was actively bad for the screen since there was no way to turn off the LCD backlight which was the weak point of the LCD screen and running a screen saver put more hours on that resulting in a faster death of your LCD.
This is a bit like studying a battle and not mentioning the enemy or the terrain, blaming the marketing department of Lockheed Martin for it going wrong.
It's just that nobody likes being corrected. Try correcting someone's spelling or grammar on any Internet forum (including HN), and you'll be hit with a barrage of "you know what I meant" and "language changes" retorts.
> It's just that nobody likes being corrected.
But then we would've had to store it in Leyden Jars.. millions and millions of Leyden Jars.
> An aside about clocks: This is as good a time as any to reset your computer's internal clock. For I.B.M. and I.B.M.-compatible machines, type ''TIME'' at the DOS prompt, and for Macs bring up the control panel. Then call 900-410-8463. You'll get a recording from the United States Naval Observatory's atomic clock, and you can't get much more accurate than that. The call costs 50 cents.
Does it still work?
There's also this, which I vaguely remember working for me years ago, but can't vouch for now: http://www.sealiesoftware.com/fringe/
I have incredibly fond memories of playing Lunatic Fringe, despite being very bad at it, and despite catching a ridiculously bad case of strep throat one year shortly after discovering it, and having some bad, vaguely-related fever dreams about.
Edit: Looking it up, the After Dark Games version of Rodger Dodger apparently has different levels from the screensaver version! (And not just in that it added ones; in fact it has fewer in total.) That's annoying...
Ben Haller still maintains a version of Satori and Rose for Mac OS X:
I always liked the screensavers, and still do. I use a gaming-friendly 4K TV for my PC monitor at home, and without the screensaver, it shuts off, and doesn't come back on, without the remote.