A Very Flammable Lampshade

I set out to build a test set of bellows today. I found a website that describes how to build a set of bellows for a camera. I modified the dimensions to produce something close to a pyramidal shape, and constructed a test model using Bristol paper for the ribs and vellum for the outer material.



I believe that the difference in dimensions for each end of the bellows that I chose is too extreme for this method. Going through the graphic calculations, the design I attempted required 7mm and 3mm ribs. The 3mm ribs are too tiny for the bellows to function properly.



It does however make a nice, extremely flammable lampshade.



The method of building seems sound, so I will attempt this again with end dimensions that are less different from each other.