I find that it works better if you print the base in a translucent material that lets some light through. I used an orange candy and it seems to work better than solid black. I printed the top using black and it seems to work great! A version of the Fruit Fly Catcher with a swivel top and a base of it's own so you don't have to use a nasty jar and watch the things fly around all day while they die. YUCK! Put a piece of fruit or some apple cider vinegar in the base and the fruit flies get trapped inside. Keep the lid on and submerge it in water to kill the flies and clean it. Easy.