It’s just a chair, but made from old floorboards, very simple and straight forward.
Front leg which becomes the back is 3′ long the angle is 15deg at the bottom.
The seat can be as wide as you like (need) and the back rests are the same width.
The other legs are cut at 30deg and can be cut to suit the height of the table you sit at.
When you attach the legs together make sure the shorter legs have about 2″ gap at the bottom, otherwise it will tip you off forwards!
I might shape the sides slightly towards the top, but otherwise its just a simple chair out of scrap wood!