They can walk with you
httpv://www.youtube.com/watch?v=67CUudkjEG4
They can follow you
httpv://www.youtube.com/watch?v=cNZPRsrwumQ
and they can chase you
httpv://www.youtube.com/watch?v=d2D71CveQwo
Bonus!
Two home-made prototypes:
httpv://www.youtube.com/watch?v=X5BPrlOVX2o
httpv://www.youtube.com/watch?v=mXI4WWhPn-U
