@Cryptozeug 23 June 2022 more from that month

In the meantime, I have been able to solve the puzzle, or rather, a colleague has been able to solve it. What we see here is the construction of a potter wasp. To be more precise, it is either the Oriental Mason Wasp (Sceliphron curvatum) or the Yellow and Black Mason Wasp (Sceliphron caementarium). You never stop learning: The oriental wall wasp is a spider-eater. To feed her larvae, the female hunts spiders, paralyses them with her venom and brings them to a potty she has built for the larvae. After 8 to 15 spiders, she adds an egg and closes the entrance. The newly hatched larva then feeds on its larder during the cold season before pupating, just like a butterfly. The following spring, a new wasp hatches from the potty.