How to build a TNT Cannon with adjustable range and direction?
So far I've seen different cannon designs such as basic guns, animal gun and the infamous 360 Gun.
But what is an as easy as possible gun design with big range covering an angle of about 90 deg?
EDIT
I'm looking for concrete desings. You may provide screenshots or vids along with a short description.
You can do this, just make something which has room for multiple slots of tnt, and adjust the amount for the range. For direction, it's a bit trickier, but you can have multiple openings to the cannon, plug the ones not in use, etc.