My original construction method wasn't ideal and I don't recommend it. Stitching to a fabric backing was flawed because that moves and sags. The trays didn't remain well-spaced and they didn't stay stuck in place. 

So this week I took it all apart. Well down to the soldered-together neopixel strips. What I effectively did there was to create strips of pixels in a time-consuming and expensive way, but with the pixels at exactly the right pitch for the cells in the trays. 

For the 'mark 2' I drilled little holes in the trays and used twists of thin wire (white outer) to 'stitch' the trays together. This worked a treat. 

Hurray for hot-glue. I used the stuff to fasten the strips of pixels to the backs of the trays. I don't know how easy this would be to remove, but we'll worry about that when the time comes. In the above picture, you can see more easily how the power and ground take the shorter snaking route, while the data line zig zags, which makes programming a bit easier.

I've done some work on my little control board. I'd made a little prototype board with sockets for a pico and various useful things connected to it like a button, a reset button, a pot. This week I took this 7-segment 3-digit display and wrote a little 'library' for the pico in my preferred language, plain C, and added that to the control board.

(Yes, this little board is from a Gotek. There are a million of these floating around in the world because everyone gets one with a Gotek and then changes it for an oled display.)

I've started to work on one master program for the pico which will include all the little demos and utilities I might want to run on it. The button allows me to cycle these, and the display shows the number. (a bit useless, because you can see which demo is running most of the time.)

The pot adjusts the brightness of the display. I might try using some kind of daylight sensor to auto-adjust that.

The video below shows me flicking through three of the demos that I have installed already. A spinning earth (which just demonstrates that I can convert pngs into 12x12 animation frames), an audio-sampler with FFT and bar display, and the plasma demo I've shown previously.