What do the stars in the Pittsburgh Steelers emblem represent?

The three shapes in the Steel mark logo are called hypocycloids. They represent the three major components of steelmaking, and have become more closely related to the professional football team than with the original company!

I am a lifelong Steelers fan. I was always under the impression that those shapes were the symbol of the Steel Industry and that the team adopted it. Can anyone, maybe from Pittsburgh, shed light

edit: from neonmik98:

yea and no. the three diamonds are from the us steel company. 7 on the way !

Crazzylver3:

The City of Pittsburgh was most famous for their oil and their steel and when the birth of the football team came around they named them the Steelers and used their steel emblem but put their name on it

The Steelers emblem is the same as the steel making companies except where the word Steelers is the steel making companies is just steel.