It's made from scrap MDF and some recycled IKEA shelf batons.
To build this project I used the following tools:
A bench hook (home-made)
Two wooden clamps (home-made too)
A marking gauge
And a sharp pencil
Step 1: Cut Stock for Base
The finished shelf dimensions are 50 x 40 x 20cm
The IKEA baton was cut into strips (ignore those random holes):
4 x 20 cm - legs
2 x 40 cm - rails
1 x 50 cm - stretcher
(If you're not using a table saw I'd only cut the top of the shelf after the base is constructed, in case of any inaccuracies)
Step 2: Cutting the Halving Joints
There are no screws or fixings in the frame, the only thing holding it together is glue and the mechanical strength of the joints - so do your best to get them as accurate as possible.
Try cutting down the two lengths of the joint (pic 1) first, then remove the remaining triangle of material.
Cut the shoulder of the joint (pic 2)
And clean up the result with a sharp chisel (pic 4).
Repeat this with all four legs and the two stretchers, test fitting and marking each pair of joints.
Step 3: The Stretcher Joints
These joints were cut with a chisel. I don't know what these are called (half-lapped T, perhaps) but they worked well with the wood. They fitted very snugly and held the back legs firm without glue.
Step 4: The Glue Up
And, depending on the number of clamps you own (or have built) glue the stretcher to the side sections (the plank across the top in pic 2 is to keep everything square).
With the frame finished, cut the board for the shelf, drill the pilot holes for the screws, countersink the holes, add screws and your done!
All that remains is to give it a nice Swedish name.
Mines called Hampus.