More 3D in PowerPoint - obstacle course!

I am continuing to experiment with 3D effects. Here is an alternative idea to visualize a number of obstacles on the road ahead. The last image (click it for a larger picture) contains some explanations on how I did it. If things are not clear feel free to as in the comments.
Does anyone know how to add a smooth moving animation to this, motion paths and re-sizing of objects do not go together?
(Apologies for the image quality as I converted to JPG instead of PNG to improve load times)