TNT cannons

Everyone likes a good explosion and I love cannons and i want to find the best TNT cannon there is in minecraft. So post screenshots of ur cannon. Now then for it to be considered a cannon it must be able to fire more than 1 shot with the only block u place btwn shots being TNT. Then explain how it works a little.

Ok so here is mine. It is a "double barrel" I only loaded one side though so that i can limit the # of pics I needed. The redstone running down the center activates the TNT in the channels the water then flows through the TNT and as everyone knows when TNT explodes in water it doesn't destroy blocks. Then the repeaters delay the signal to the TNT blocks that go flying (this one has a max of 4 TNT per shot currently). The TNT in the channel then explodes sending the TNT shots flying.