well, the work table was woodworking too, but that doesn’t count. These are the frames for the seat.

start off with a trusty French Curve.

The seat overall leans back a bit, but drops at the nose for thigh clearance when pedaling, and rises at the back to hold one’s butt steady. That French curve is about 4k years old!

The part labeled master was used to make a router template.

Next was some braces, triangular, about 3” x 3/4”, usage shown later. A quick n dirty jig helps here.

the seat bottoms are glued up with the triangular braces to help offset the tension of the elastic webbing.