There are a few things you need in order to build a cannon in Minecraft Xbox 360. The first is an obsidian block, which can be found in the world of Minecraft. You will also need a furnace and an iron block. The next thing you will need is a TNT detonator. Finally, you will need some coal and water to create the cannon. To build the cannon, start by placing the obsidian block on top of the iron block and TNT detonator. Then, place the coal and water on top of that. When everything is built, use the TNT detonator to fire the cannon.
