Rebate!

Alas, this is not getting money back (although this is a legitimate business expense, I believe).

A rebate is a groove in a bit of wood. In this case, I am adding strips of wood to make a platform for the acrylic, but I decided I liked the word ‘rebate’. Square-cut pieces work well, but I happen to have a tenon saw and a box, so I cut mine at 45 degrees, and made them a quarter of a millimetre too long so that when tapped in they held by their own length. I added glue as well, but did not need to screw them in.

Now, it is a matter of waiting for acrylic.