I just stumbled across this. I haven’t tried it yet. (It’s printing now.)

I had not heard about this interesting discovery!

https://www.printables.com/model/221119-knuths-packing-puzzle

“In 1978 Hoffman proposed that a if you take cuboids with size A×B×C, you can always pack 27 into a cube that has edges of length A+B+C.

In 2003 Knuth showed that for a special subset you can fit 28 cuboids into a cube.”