I know this may be a weird question, but what are the lines on an AUX cable for?

[BigB123]

Its always had me wondering what they are for and me and my friends joke around that whoever has the more "black lines" on our aux cables, means they have the better head phones (Obviously i have the better ones even though theirs has 3 lines *cough * beats is crap *cough*). But is there even a difference of a cable with two lines, compared to one with 3 ?

 

[thisguy365]

Talking 3.5 mm audio?
A standard set of Headphones(Without MIC) would have 2 lines to create 3 contact points. One ground and one for each side.
A Head set(with Mic) would have 3 lines and 4 contact points, ground, right, left, and mic