So I can now confirm these DO have some sort of “memory” for their location. I cut off 10 from the end of a strip of 200, and cleaned the ends (lighter to burn off lacquer coating on wire, use sandpaper so you see shiny metal), soldered to a connector, and hooked up.
With a single normal pixel first (which wasn’t RGB, it was GBR, but…), these still insisted on being 192-200(I couldn’t get the last pixel to light correctly, even telling PB I had 205+ pixels. Either it was off or it would do just red).
With NO pixel in front, these behaved perfectly… told it 200 pixels, and it was 191-200.
I’m going to try some Ys next.
These are cool, I see so much potential.