Sprung Solo Seat Base
These are patterns for a Bates style sprung seat base. Because of their size, they're split across two pieces of paper. The idea is that you print off all four of them and join the separate pieces to make the entire pattern.
Cut the base from something like 1/16" steel, maybe a little thicker. Cut out two of the formers from 1/2" or so thick ply or MDF. Bolt a former either side of the base, and beat the sides of the base down over the formers, and the rear of it up over the formers.
When the base is seat shaped, stop beating it. You'll need to make a "T" shaped thing out of steel strap to go from the front two bolt holes to the left and right spring mounts if you want to use it with an aftermarket seat hinge and springs.
If you right click on the thumbs, you'll see a menu and you can either choose "Save Target As", or "Save Picture As" to download them to your computer, from where you can print them off. You'll need to check that the printer isn't shrinking the image to fit the paper probably...