I've put together a new video showing how a zone-based control system can do "gesture-like" things, such as raising and lowering one's hand to control the brightness of a light.

In order to make gesture-like features work on low-power systems with weaker CPUs, I use an approximation that I'm referring to as "center of gravity" for lack of a better term.  The approximate center of gravity of the objects in each zone is used as a control parameter in the automation system.  Watch the video for details.