I've always liked how minecraft cannons were built, but they were always too wasteful and time consuming to be used realistically. I set out to change that. Cannon powder works exactly like tnt, except it doesn't remove blocks or damage entities. It's used to push things. I also hooked up the dispenser to spit out live TNT / CannonPowder instead of just the item.You can use it to create cannons, elevators, traps, etc.The recipe is shown in the video. Visit the minecraft forum thread for discussion and feedback.