[ale] DIY Graphing Calculator Is Built From Open Source Hardware

[Tom Freeman]

On Fri, 6 Aug 2010, jcpilman at gmail.com wrote:

> I still have a couple of slide rules which I began using before high
> school.  My wife owns a circular rule that does not have sliding
> disks, but instead has two movable cursors (not sure they were called
> cursors).  It worked on the basis of constant angle between the
> cursors.  A 10 inch circular slide rule has the precision of a 25 inch
> linear slide rule.

I never bought a circular slide rule, on the grounds that I couldn't see 
hanging one on a belt, and they sure wouldn't fit in my pocket 8-). Maybe 
I should break down and get a circular rule just for the giggles and 
confusion of my students...