Yellow - - - - - representing the Cavalry and mobility

Blue - - - - - - for the Infantry and holding power    

Red - - - - - - signifying Artillery and firepower      

The overall shape suggests a pyramid of power, with Patton's branch and color (cavalry yellow) uppermost.

The lightning, tracks, and cannon were added in 1941 when the Armored Force was reactivated.

The individual unit designations are indicated by the number at the top of the patch.

(Note: This information courtesy The Purple Heart Magazine)