Tanks: aiming, image points and attaching

1. Add the Vehicles and Combat extension.
2. In the chassis paint editor, use the Image points tool (P key) to create the point turret. On the turret, create the point tip at the end of the barrel.
3. On the turret: attach my position to point turret of Chassis and turn along: no.
4. Inside a "forever": smoothly turn toward mouse pointer up to 6 degrees at a time.
5. To shoot: create clone of Bullet at my point tip pointing my direction. The bullet only needs "move 12 steps" until it touches the edge.

Attaching is applied at drawing time, so the turret never lags behind the tracks. See the ready-made example Tank battle.