What is it for?
The first one lights up when Num Lock is pressed, the second one springs into action when Caps Lock is pressed (even when it is accidentally pressed, reminds me of someone who "trained" his assistant to not accidentally go into caps by blu tacking an upside down (sharp side up!) drawing pin onto the caps lock key) but I can't work out what makes the third one light up?
Lame Limericks (but they are funny anyway) (