Ok. So while in my trig class, I had an idea for a ball point pen that, when writing, it has an automatic mechanism for making dashed lines. I mean to say, it lifts the ball point or obscures the path to create a perfect dashed or dotted line, or allows to draw a line of fixed length for measuring before writing. My first inclination was some sort of really basic mechanical calculator, in the pen, to calculate the distance the ball has rolled. Problem is, I don't know anyone who can help me figure out what to do. If anyone understands how these things work, I'd like help designing a prototype for now. Thoughts?