Made from cardboard and paper and painted with acrylic color. It has bowed down a bit in the middle since then, but it's still fine otherwise.

I kept "running out of space" when trying to build the apk for delta chat. Turns out it's trying to build in /tmp, which has a hard limit of a few GBs on Ubuntu; I just need to remount it with more space Can someone mention this in BUILDING.md?