A test tube holder for witchcraft magic potions/chemistry, with a wood structure look.
Holes are 12.5 mm diameter.

Imported multiple instances of the Tiny Wooden Plank by Orbnotacus, scaled and positioned them in order to create this structure. Then I added three cylinders and assigned a series of boolean operators to calculate the 'difference' between the holder and the cylinders; thus creating the holes for the test tubes. I gave the cylinders a little bevel on the bottom end, such that they create a nice indentation for the test tubes to settle in.