Two Nybbles (SP0T and L0R) hang out in my living room. Each is running @Gero 's ultrasonic sensor implementation and python automation script. The script executes automatically on boot, so each cat is self contained – I just switch em' on and set them loose.
It'd be super interesting to give the cats an awareness of each other and develop shared behaviors. This is a bit beyond my novice coding abilities, but I'm eager to experiment. For now, these two anxiously await their Bittle bro!