At its core, a chair is simply a seat with a back. And while they often have legs and arms and complex joinery for strength, sometimes, a little physics can accomplish the same thing.
Instructable member More Cowbell shares his simple plans for making a minimalist, stow-able chair from one 8' long, 12" wide pine board. It s basic design allows it to be disassembled and stored flat in standby mode under the bed or in a closet for parties, barbecues, or camping trips.
The technique involves cutting a large mortise - or, as More Cowbell dubs it, a slot A for tab 1, - to insert the seat, creating rigidity and a comfortable sitting angle. The wood costs less than $10 each, and can easily be sanded, stained, or painted.
Get the full how-to and measured drawing at Instructables: One Board Minimalist Chair