🚀 go-pugleaf

In article <1992Oct6.121036.15029@sei.cmu.edu> firth@sei.cmu.edu (Robert Firth) writes:
>In article <1992Oct6.030213.20215@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:
>
>>The compass is nice because it works straight from the definition of a
>>circle, while a ruler, as you note, is not so nice since it does not
>>work from the definition of a straight line as the shortest path between
>>two points.  However, there is a machine that has been built which draws
>>straight lines "by definition."  Alas, I forget how it works.
>
>Gee, we did this in school - don't they do it any more?  You draw a
>straight line by taking a thread covered in chalk dust, and stretching
>it between the two points.  Then snap the taut thread against the
>blackboard to get a chalk line.  That "machine" does follow from the
>Euclidean definition.

Okay, everyone is pointing this out, which is good, but I had in mind an
infinitely more complex apparatus that I saw in a book somewhere.  The
used to make all sorts of mechanical gizmos with wheels and such that
allowed one to draw various mathematical curves, and I think someone
designed one to draw a straight line.  Admittedly silly, but fun.  

In short, my rules are: make it out of solid hunks of steel (no steel wires).