I feel these awesome devices need a thread here.
Post your designs and inventions here!
Here's my multifire cannon. each cannon is connected to an AND gate, which get their inputs from a lever linked in the control room, and a button. This basically means that when you flick 2 switches and hit the button, two cannons will fire.
*I have 111 of some materials as i used TMI to get TNT and water, as this is a fresh world for cannon testing.