[DGD] Differential Calculus

[Shentino]

Ok, I just had an interesting idea...

I was doing something similiar in a physics simulation, recording
position, velocity and acceleration to do an event-driven as opposed
to timer tick driven simulation, and thought maybe it could be
extended.

Pros and cons of recording rate of change in stead of periodic updates
every heartbeat?  I think it would cut down on the number of callouts,
but it might increase CPU time with extra number crunching per query.