Certain persons to whom I am married like DC comics and those infinitely-reflecting mirror things. This suggests certain Valentine's Day presents.
Infinity mirrors, it turns out, are pretty simple. You need lights around the inside edge of a box, which is really easy to do these days with LED light strips. The ones I got could even be snipped to desired length. The bottom of the box is mirrored (I used inexpensive glass mirror tile). The top is half-mirrored. That's a little trickier, but there's inexpensive window insulating film for that. The only innovation on my part was firing up the CNC machine to engrave a bunch of superhero logos on a sheet of acrylic to use as the top. That was a delicate operation. The carving required very, very shallow cutting, so it was very sensitive to the slightest bend in the material. Sandwich the semi-mirrored film between two sheets of acrylic (one engraved), assemble, and: