Gnat Funnel!

So maybe not for gnats, but this is a 3d printed approach attempt to trap those pesky fruit flies that comes with your bushels of supermarket bananas.

My wife had been using the rolled up paper funnel+ball pickling jar technique for a couple years with success. Google for details what to use, but we've been filling bottom 1 to 2" of the jar with a water, vinegar, and dish soap solution.

Disclaimer: I've not yet put the 3d version into the field, so don't know if it'll work compared to