A Wise Old Master Chief once Said...

 

A young sailor approaches the crusty old Master Chief and asked about the origin of the commissioned officer insignias.

"Well…"
 
… replied the Master Chief …
 
"The insignias for Naval Officers are steeped in history and tradition. First, we give you a gold bar representing that they are very valuable but also malleable. The silver bar also represents significant value, but is less malleable. Now, when you make Lieutenant, your value doubles, hence the two silver bars. As a Captain, you soar over the military masses, hence the eagle. As an Admiral, you are, obviously, a star. Does that answer your question?"
 
"Yes Master Chief."
 
… replied the young sailor …
 
"But what about Lieutenant Commander and Commander?"

"That, shipmate, goes waaaay back in history - back to the Garden of Eden. You see we've always covered our pricks with leaves."