just like jonathan said, you can do that with data structures, just add
the parenthesis scales to the variable declaration. I just don't leave the
limit in, because you can still define extreme positions (for example,
controling the points with messages instead of mouse click).
João Thanks for the zip. The abstractions are nice. I wonder if there is a way to keep from moving the control points out of bounds on the bezier. With a slider or numberbox it is easy just store a limit in an f and when the slider value changes check to see if it is beyond limit then do a delayed message to the slider to set the value to limit. You could even put a message to canvas label "beyond the outer limit" haha!.