Hexagonal shelving looks neat but requires a relatively high level of woodworking prowess to make flawlessly because of the awkward joints. Connecting hexagonal units also creates a slightly odd feature where the internal sides are double the thickness of the outside. In order to solve both these problems, I designed some 3D-printed joints that allow quick and easy assembly of hexagonal shelving. Extend them as far as you like. I've provided all the files for you to print your own, with assembly and mounting done through predrilled holes with drywall screws.

Step 1: Joints

The idea was simple - make a joint with built-in dadoes for the shelving material (I used 1/2" plywood) and countersunk holes for the screws (offset to avoid clashing). Mounting points could also be included, and with a mind to designing for 3D printing, each joint could be printed without the use of supports. All design was done in Fusion360.

There are multiple forms of the joints, with 3, 2 or 1 shelving inserts. Print them all with 3 inserts for maximum future flexibility.

I printed the joints on a Creality Ender 3 out of black PLA using 20% infill and a 0.2 mm layer height. Make sure you have the front of the joint down when printing. Each joint took about 5 hours and used about 30 g of PLA. So certainly not fast, but the small footprint means you can print them all at once and leave your printer to chug away for a few days. The STL files are attached below. The Fusion360 files: 1 shelf, 2 shelves, 3 shelves.

As is often the case, I always assume I'm the first to think of an idea, but at least the bit about using 3D-printed joints for hexagonal shelves has been done before, on this very site (and entirely possibly elsewhere). The look of those ones is quite different from these ones.

Step 2: Shelves

Get some 12 mm (1/2") plywood (or if you're feeling fancy, mill some solid wood to the same thickness). Each piece must be 130 mm (5 1/8") wide but the length is up to you! Depends entirely on how big you want the shelves to be. I made all mine 230 mm (9") long (for the sole reason that I had a strip of leftover plywood this wide). This made each hexagonal unit able to hold 10-15 books - good for a small library with some space on top for other items.

Paint or polyurethane the shelves if you're so inclined. I didn't bother disguising the edge of the ply; I liked the industrial look in combination with the lines on the 3D prints.

Step 3: Assemble

Assembly is super-easy. Just slot the shelf in place and drive two 1 1/4" drywall screws through the holes on the opposite side. Sink the screws until they're flush. The joints are rock-solid, impressively so. If you decide you want a different configuration - just unscrew and reassemble, the design is flatpack-able.

The unit shown has the same framework as the naphthalene molecule; there are lots of other polyaromatic hydrocarbons that make for funky looking shelves.

You could also extend the molecular analogy further and make functional molecules such as dopamine, (structure shown above), a neurotransmitter that conveys motivational salience, or more popularly, the pleasure chemical.

Step 4: Mount

Screw into the wall using screws and/or drywall anchors, and fill with whatever books or artifacts you want to display. Hexagons are never going to be the most efficient way of storing books, but it's a bit more interesting than your average set of shelves.