[jpecar]

I still don't get what

POKE 23641,194

RUN

does on zx spectrum. And you get different patterns for different values, say 197. And wait for a minute or so to see something even more interesting.

[rwmj]

I tried this on a Spectrum emulator (https://jsspeccy.zxdemo.org/ - select 48K BASIC, then use the "O" key to enter POKE, then "R" to enter RUN).

The two bytes at that address and the one following are used by the BASIC ROM to track the command you're typing in, so maybe an artifact of how the ROM works?

[jpecar]

Yes, this makes magic on real hardware and I see it do nothing on emulators. So something really funny must be going on here ...