An experiment in manipulating a particle system.
Use the mouse wheel or q/w keys to change tool.
Pointer affects nothing.
Hand allows you to drag spawners and pull/push forces.
Remover destroys spawners and pull/push forces on click.
Pen allows you to draw collision walls for the particles.
Add (PullForce/PushForce/Spawner) creates a new appropriate object at the cursor.
ClearLines removes all collision walls.