hmmm,I don't know if I'm able to tell the difference between machiene made slags and swirls,well I'll try.
The machiene made slags such as CAC (1 or 2 seams) Peltier (feathered) are easy to distinquish from the machiene made slags by Akro.
Akro slags are difficult to distinquish from swirls.
The white ribbon in a swirl can have sharp curves,like a V or L.
A slag usually has more round streamlined ribbons.
A slag has Always a colored or clear transparant base with a white ribbon.
A swirl can have a little or much color running with the white,and the base is usually not as bright transparant as a slag.This is what I see when I look at my slags and swirls.