I think a picture might be worth a few words here...!

The bottom bar is grounded, and all circles (aside from the middle of the top and bottom bars) are revolute joints. There are motion links such that joints on opposite sides move symmetrically, ie. equal but opposite angles. What you do is push up and down on either of the middle crosspieces, and the top bar moves up and down but at greatly reduced scale. It's basically a (flexure) linear stage.
Since the motion of the top joints is so tiny compared to that of the middle joints, those angles are not useful for figuring out exactly what the positions of the crosspieces and top bar are doing. Of course I can push it a little, inspect the x,y positions of say the center joint and the center hole in the top bar, and graph accordingly. But that's kind of a pain to do over and over. I tried dimensioning the distance between holes, but that doesn't update when I push the crosspieces around. Same if it's a parameter.
If positions (or dimensions or parameters) could be observed in a window somewhere, that would be extremely helpful. Better still would be a button that would enable 'position tracking' of some sort, which I could imagine generating a csv file of the relevant data.
The point of the whole thing is to make a microscope stage with at least micron-scale movements!
Hope that helps clear things up a bit...
tnx,
Patrick