"Pete C." wrote:
>
> Any CAD program can calculate the area of the two sections as you scale
> the nozzle, so it shouldn't be too difficult to make a star, heart, etc.
> and scale it until the ratio is correct. You probably also don't want to
> machine a tube, but rather machine a mandrel that the the tube can be
> pressed / hammered around so it has the correct profile without excess
> thickness to the outside material will flow in the correct matching
> pattern.

Good point. That is the right way to do a precision shape.
If the tube were thin enough and made out of brass or
something more ductile than steel, I might be able
to make a crude star by grabbing the edge with
needle-nose pliers and twisting it to form a point.