just found out about the app today one of the few saying it's to show off the 3gs so I thought I pass it along. I just downloaded it myself haven't tried it yet myself! IGPU Trace Note: This program only works on the IPhone 3G S, since it uses the new GPU of the IPhone 3G S for realtime raytracing. Do not purchase this app if you have an IPod Touch or IPhone 2G/3G! IPhone GPU Raytracer is the first real-time raytracer for the IPhone 3G S. It utilizes the PowerVR SGX GPU for raytracing using OpenGL ES 2.0 shaders. The compass and accelerometer controls the camera movement in 3D space. The Settings tab allows to enable an environment that is mirrored on the scene objects. If you have red-cyan glasses available, you can see the scene with real depth by enabling stereo mode. A one finger drag rotates the camera around the object, a two finger pinch is used for zooming and a three finger drag translates the camera.