This chart shows the build tree and more for The Army, one of three races in Cannon Battle.
The Army specializes in Shrapnel damage. The Others will specialize in Energy damage, and The Kingdom will specialize in Fire damage.
This represents a very lean and mean spec. Obviously we could go crazy with the premium content, and create dozens or hundreds of Structures, Commanders, and Choppers.
This is very much a work in progress, but nevertheless conveys much important information even in its current state.