🚀 go-pugleaf

In article <1992Oct6.030213.20215@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes:
>In article <1992Oct5.154211.21663@ecrc.de> micha@ecrc.de writes:
>>In article 24242@access.usask.ca, choy@skorpio.usask.ca (I am a terminator.) writes:
>>>How do you know that the line you draw is really straight? What
>>>defines straightness?
>>
>>This is something I've been wondering about since a long time. Although we can
>>make a circle as precise as we want, I think we cannot make a really
>>precise straight line
>>
>>	    [...]
>>							 IMHO there is no
>>process to create a straight line directly. Or is it?
>
>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.
>
>	[...]

I'm sure this isn't what you were thinking of, but out in our garden, we
often make straight lines based directly upon the geodesic principle.  That
is, we take a piece of string, and stretch it, so that it takes the shortest
path between the two points.  Not very high tech, but it seems to work well
enough for the garden, and I would imagine the basic technique could be
improved to give the sort of thing you were asking about.

Chris.
-- 

Chris Gill, Postgraduate Group Theorist
Department of Mathematics, University of Nottingham, UK.