qole, I already do.
I work on strokes remember

Then, there is the knowledge that a single finger moves in a linear track, if it happens to jump a large distance (bsg.hybrid.jump()) I can say:
"ahhhahhh you broke the laws of physics and an additional mass has pressed on the surface"

Once I have taken that step I limit the equation by asking that you maintain this first thumb in place, this acts as the pivot point.

I just monitor the filtered new results and use that to mean the second finger.