Made a chair.
The idea was to make two, but time was short. One is better than nill. You could make another one, or something similar if you want to.
Steel cut 45 degrees at every end for a mitre joint
Welded 2 metal pieces to hold the rectangles together and to support the sitting fabric
The fabric is laced together in the back with a nylon cord. This makes it easy to regulate the sitting height.
The red fabric in the top pictures is a thick plastic(PVC) fabric reinforced with fibre. This is only temporary to show the idea and how to join the fabric in the back. Final fabric could be wowen wool or some sort of leather maybe?
The steel is raw and dirty and can be brushed and treated with owatrol like the shelves.
I will upload dwgs with discriptions on the shelves and the chair to the Drive later today.