Using Shapes on Mobiles to confuse optic flow sensors in Micro Air Vehicles appears to be feasible. Today we are studying the flight paths of Bats, Insects even birds to build and fly miniature UAVs; called Micro Air Vehicles or MAVs. There is significant research being done on this. The goal is to have mini MAVs the size of dragonflies, about 15 CM, which are autonomous and can fly through tunnels, under tree lines, under small bridges and navigate around obstacles. By using the optical flow sensors a new technology of mind boggling proportions the tiny MAV would take send out pulses and capture images, as the next pulse sees the image again it is bigger, this way the tiny MAV can sense when it is really big and getting close so it can then fly around it. There are two ideas, one is to use a single sensor unit and the other is to use multiple sensors. If you have ever studied insects, how they fly and navigate, you can see the enormity of the mathematics and algorithms it takes to make all this happen. Here is how it all works you will have to read all of these papers to understand this concept and to continue such discussion;

http://www.centeye.com/pages/resources/downloads.html

By the way compliments to Geoffrey Barrows for his studies and insight and recent award. Thus creating the fuzzy logic and sets of rules to determine what is an obstacle and what is another moving object. If you read one of Tom Clancy