Just realized Ikea cable organizers work great as diffusers. What else have you used as diffusers for your projects?
That is a great idea. I went to goodwill and bought an old bedliner and cut it to size and wrapped it around some poles. https://www.youtube.com/watch?v=Hrac76n84lc
Yes! I just bought 5 m of this stuff a couple weeks ago but haven’t tried it out yet. It looked like the perfect thing so glad to see it working well. If anyone else is interested it’s called “Rabalder” at Ikea. I think the 5m length was around $5 or so.
it’s called peszel or Rura elektroinstalacyjna karbowana. http://www.ttplast.com/pl/rura-elektroinstalacyjna-karbowana-bezhalogenowa-320n-rklshf 
Among other diffusers, I use white split loom tubing or pool tubing.
Ping pong balls for pixels.
For my matrix, I used a piece of polycarbonate plexiglass and sprayed one side of it with frosting found in the spray paint section of my hardware store. I can’t find any kind of pre frosted glass or plexiglass for as little as I payed doing this.