Modular modern shelf made in Spain

This is a very versatile modular shelf. No screws are needed! They assemble as a LEGO.

The smaller ones are 27x27x36 (depth, width, height)

The larger ones are 27x54x36 (same order)

There are 15 of the larger ones and 6 of the smaller ones.

Some of them have an extra shelf inside for separation (like the top corner on the left of picture number 2), but that can be removed or placed somewhere else.