"According to the top researchers of the Fraunhofer-Institut für Arbeitswirtschaft und Organization (IAO) in Stuttgart, the human mind is set up to work at its best under the open sky, with changing illumination caused by clouds passing overhead. The unvarying glare of office lighting is sub-optimal, therefore, and in order to wring the last ounce of efficiency from German workers whose productivity has already been pushed to unprecedented heights they have decided to rectify this with a LED cloud ceiling."

Speaking of cloud ceilings, 
Part One:
http://www.redicecreations.com/radio/2011/09/RIR-110929.php
Part Two:
http://www.redicecreations.com/radio/2011/09/RIR-110929-SUB.html