How to soften butter in the microwave

This is so great! It works every time. 

Place the butter on one end and microwave for 4 seconds.  Then turn it on the other end and microwave for another 4 seconds.  Then lay it flat and microwave for 4 seconds.  Then flip it over to the opposite side and microwave for another 4 seconds.

If I'm using margarine I shorten the time to 3 seconds.