So I took this tutorial and made my own with a few tweaks. Thank you OP for the great idea! I found someone with 100 CD cases on freecycle. This is smaller than the one in the tutorial because I didn't really design it to split a room- more to put some color on the wall since we can't paint (well, we can, if I paint it back to white before we move out and I feel like that's a lot of painting when we're only here for another 10 months).
all my case panels hot-glued together-

Painted, halfway-

Then I added some silver with a rag bc the color was REALLY intense-

The tree part is done!

Wiring it together...it's kind of hard to get a good picture of it.

I'm semi-obsessed with making things reversible, because I get bored but I spent a lot of time on this and I'm not going to scrap it when I want to change things up! I also read about the problems with the hot glue sometimes not holding on its own, so I found some printed tape at the craft store and used that along the edges- I might do it on each square later like a grid. Then I put pictures in it, so if I get bored I can just flip it over and have a handy dandy photo mosaic of sorts (that's me and my husband snorkeling on our honeymoon


Finished!

I'm pretty jazzed about it even though it didn't turn out perfect. I wanted to add some writing of quotes or something but my handwriting is sort of unattractive, so I might add that later. Thanks again for the tute!