Ever hear of a thing called RGB? Red, Green, Blue? How about an RGB LED? These 5mm units have four pins - Cathode is the longest pin. One for each color and a common cathode. Use this one LED for three status indicators or pulse width modulate all three and get mixed colors!
Note: Pins 3 and 4 are switched in the datasheet, in actuality pin 3 is blue, and pin 4 is green.