The origin of the Schwedenstuhl design is unknown to me. It is used by German scouts. There are different variations (see www.schwedenstuhl.de for different construction instructions), but the basic construction is always the same: The chair consists of two parts (seat and backrest). The seat fits inside the backrest for transportation or storage. It is plugged into a slot in the backrest to form a chair.
The original Schwedenstuhl construction boils down to "cut some pieces of roof lath, screw 'em together and staple a towel to it".
In this project, I try to put a bit more work into one to make it look and feel "deluxe". This includes higher quality wood (re-use of an old but robust slatted bed base), some woodworking, self-mixed paint and beeswax finish.
An important detail is the gap for the seat to go. Instead of 90° there is a slope of 10% (6,5mm for 65mm width). The square piece and the two flat pieces are glued. The upper parts are NOT glued, because they are used to clamp the backrest fabric down.