This prints as a set of two parts: A well shaped a bit like a volcano with a filling crater at the top, little tunnels to let ants into the crater, and a lid with a centring stem to keep the rain out. The aim was to have something stable I can put ant poison out in without worrying about what our stupid cats will do.The shape I settled on is a broad, flat cone for stability and to lower aerodynamic drag - it's vaguely reminiscent of the tornado ground cameras. The central well is a 45 degree cone to discourage sloshing and to make it more likely that your RepRap will produce a watertight object!Print, fill crater with about 10 drops or so of liquid ant poison and use as per directions on packet. Put the lid on to keep out rain, debris, hummingbirds etc. The ants can still sneak in under the lid and light rain will probably not get up the sloping, stepped tunnels. Really heavy rain will get in, but will also hopefully sort your ants out.To make your own ant poison, mix 1 heaped teaspoon of borax with 1 heaped teaspoon of sugar and enough (maybe a tablespoon or so) of boiling water until it mostly dissolves (I shake it in a bottle with a rag round it). Then dribble in about 1/2 teaspoon of honey, treacle, or whatever your ants are going for. I keep mine in an eyedropper bottle, clearly labelled on the poisons shelf.If you bait the trap with some plain attractant first, their little chemical trails build up and you get more visitors. Then the queen and grubs get a lot of poison all at once.