Billock, Cunningham & Tsou (2008) 12 APPROVED FOR PUBLIC RELEASEmuch utility in describing the natural environment and make it such an elegant solution to the problem of designing camouflage) also prove to be its Achilles' heel. Author Note and Acknowledgements Vincent A. Billock,General Dynamics, Inc., Suite 200, 5200 Springfield Pike, Dayton, OH 45431 ; vince. billock@gd-ais. com. Douglas W. Cunningham, University of Tübingen, Tübingen, Germany ;douglas. cunningham@gris. uni-tuebingen. de. Brian H. Tsou, AFRL/RHCI, Wright-Patterson Air Force Base, OH 45433 ;brian. tsou@afrl. af. mil. We thank Jer Sen Chen, Steven Fullenkamp, Paul Havig and Eric Heft for technical support.