@mur2501 .. wow. I have yet to see a Computer Science student here doing that. We had to study lots of maths and logic, but not drawing, heh.
The roller rulers are intended to be a cheap replacement for a proper architect T-ruler or the wire fixed equivelant. A T-ruler only works on an architects table where a roller ruler you can use on any notebook anywhere.
The idea is that you can move the ruler up and down and the lines will remain parallel and fixed as long as you dont lift it. Then you can pule triangles or protractors on top of it to create various angles.
@freemo
Probably wouldn't be a course here anymore. Since the HBS is long gone (it's become the VWO I believe) the focus shifted. I'll ask my dad sometime about it. I've seen some of his engineering drawings, somehow he still has them. ;) He hated that course though.
@mur2501