This paintball mine is based (i.e. ripped-off) from a patent I found online. (US # 6,688,234 B2) Browsing patents online is a great way to come up with cool ideas for your own projects! The mine is a small canister that you bury in the ground, filled with liquid paint. A standard 12 gram CO2 cartridge is inserted upside down into the canister. A top with a plunger centered over the cartridge is screwed on. When someone steps on the plunger the cartridge is pierced, pressurizing the canister and expelling the paint. I feel the original patent has a simple, but serious design flaw. Look at Diagram #1 below. When the CO2 is released it follows the path of least resistance, and blasts directly out of the holes, carrying some, but not all, of the paint with it. It also tends to create more of a thin “aerosol spray” with the paint. Diagram #2 shows my design, which adds tubes/nozzles in the holes with a small gap beneath them. When the CO2 is released, it cannot travel down to the tubes, so instead it pressurizes the canister, forcing almost all of the paint out before it can escape out through the tubes. This results in more of the paint being expelled in a thicker and more forceful stream.