Introduction - If you have any usage issues, please Google them yourself
STICK Calculation of the tip of a pointer with 2 markers in known positions
[TIP,D]=STICK(P1,P2,RL) calculates the instantaneous trajectory of the tip
of the stick mounting the markers with trajectories P1 and P2 and
having the tip at the distance RL P2 the distance between
the 2 points P1 P2 is also provided in D.
The tip is calculated on the line joining the 2 markers at a distance
RL the second in the 1->2 direction