Occam's Funnel

Why are funnels made round? By making them round, the funnel will effectively work as a lid, and air cannot escape, causing the need to integrate a ventilation channel. I thought about this and realized that making it non-round will solve this problem.

By adjusting the $fn parameter in the supplied .scad file, you can choose how round you want the funnel to be, along with height and diameter. 

To be printed in “vase mode”. I also bump the extrusion rate to x2, but that can be a matter of opinion.