This is a lampshade with more or less the shape of a droplet.
It's meant to be covered with some kind of paper/fabric.
It's just glued together. The pdf with the sides should be cut (almost) twice.
Possible improvements: It's way too fragile. It broke in many places and I had to cut replacement parts. And some of the circles are so close in size that it's really difficult to tell which is which.
It would also be way easier to mount it if a light bulb could go through the top hole.. But maybe less elegant.