An Android Experiment developed with Google featuring face detection and procedural animation.

Cute little creatures crowd the screen. But as soon as they see your face, they all run away! Try sneaking up on them to catch their antics before you are spotted.

Boo! was developed with Google as part of their Android Experiments program. The app makes use of the front-facing camera of the device. A face detection algorithm determines if the creatures are being watched. Their movements are governed by spring/mass physics simulations, and they are drawn purely algorithmically with no bitmaps or canned animations.

More details are available on the project page at and the code is open source on GitHub.