An 'emitter' generates points with a velocity This requires some sort of reactor to push the particles.

A single point can emit through an one direction, arc, or full pi a line emits along it.

Each can be performed with split lerp.

e = new Emitter(200, 300) //point
e = new Emitter(Line) // alone a spline.
newPoints = e.step()
allPoints = e.points