By "cannot" i assume you mean you watched the demo video but your life is too short to waste it on video explanations of assembly tricks that are much better done in text? :)

Or he's somewhere where enabling audio is not an option.

Some people have sight problems, or are even totally blind. But they still use the Internet.

Yeah but the OP sounds like they saw the demo and are wondering how it's done now.

I don't know about the GP, but for me it meant "I have ten seconds to understand this curiosity, but not 32 minutes. If someone wanted to spend ten seconds explaining to the rest of us, I'd be grateful".

The demo shows nine separate sprites, even though C64 supports showing only eight. It starts off by separating them vertically, which is a common trick, but then moves them all to the same raster lines and overlapping locations, which is much more surprising.

There are some basic debugging notes by Martin Piper: https://github.com/martinpiper/DebuggingDetails/blob/main/Ni...

For better understanding: The demo starts with a magician character drawn in the center of the screen, announcing the trick in text (some of this is big text achieved by overlaying sprites). Then, 9 sprites, each in the form of a colored number from 1 to 9, exit the magician's hat to rotate around him (in the notes screen #1), then, the screen gradually widens horizontally beyond the usual borders and the circle of the 9 apparent sprites spreads out over the entire screen (screen #2). (At this point, the display of the magician, which was clearly drawn by PETSCII characters, before, shouldn't be viable anymore.) The swirling numbers transition to a narrow ellipse near the top of the screen (screen #3), which then transition to the very top of the screen, above the normal display area, a zone, which is available for sprites only, showing the sprites in a linear rotation (screen #4). Meaning, these must be sprites and these 9 apparent sprites are drawn at the same scan-lines. (So there is no way this could have been achieved by conventional, vertical multiplexing. This is the highlight, the big trick of the magician's show.) At the end, the sprites return to their initial circling motion and vanish, one by one, into the magician's hat.

The demo is a combination of various tricks and artful timing, which enables perfect transitions between them.

Video of the explanation, at the timestamp showing 8 sprites that look like 9 sprites: https://youtu.be/Ik1vsMM2EuY?t=1509

> the last two Sprites there are multicolored mode; (...) we have a different number of of high res mode Sprites and multicolored Sprites and expanded Sprites; and those high res and multicolor and some horizontally expanded Sprites are all munged together and then the apparent view with animation of the Sprite data as well the Sprite frames (...) gives an apparent view of having nine independent Sprites; but we know it's not, we know that it's a great big blob of eight Sprites all grouped together horizontally (...)

via youtubetranscript: https://youtubetranscript.com/?v=Ik1vsMM2EuY

The music is very, very good too.