Outdoor Origami Meeting Module (OOMM)
I came up with this unit on the train back home from the 14th Outdoor Origami Meeting in Kraków, hence the name. This unit can be used to make spiked versions of polyhedra with triangular faces as well as polyhedra with square faces where each face is extended with a ”bump“.
After publishing this unit, I found out that Natalia Romanenko had published a very similar unit, the Cupolas, before me. Main difference is that her unit is made from 2:3 paper while mine is from square and as far as I can see (I don’t have instructions for Cupolas, only pictures of finished models on the web), in her variant the triangular part is the top layer of paper while in OOMM it is the rectangular part that lies above the triangular part.