Day 6. Old Kuka Meshroom
I briefly worked, as part of Google Robotics, at a wonderful place called Bot + Dolly that made artwork with giant robots. Everything they did was inventive and playful.
They had this ancient Kuka 6-DOF robot that they had acquired from parts unknown. They never got it to work, and eventually sold it for scrap. On the day before it left, I took a few hundred photographs of it, and used them to do photogrammetry inside the open-source software Meshroom.
This took about 10 hours to solve, and the rendered image here is just the viewport preview from inside Blender.