Stands for test tubes
I needed two stands in my laboratory for test tubes of different sizes. You can buy them, but it is far more fun to make them yourself with a laser cutting machine. What's more, I could make as many holes as I needed, and of the right sizes, too.
I cut round holes of different sizes into plexiglass with the laser to create a base and upper board for the test tubes. I subsequently made little holes in each corner for screws with which to support the two boards.