Posted by BillS on October 04, 2006 at 15:49:12:
In Reply to: elliptical cardan gears posted by tompeat on September 29, 2006 at 10:52:45:
I don't know about the elipticity or squareosity of the two gears (2 made-up words in the same sentence!), but this link shows an animated cardan gear set including words about its inventor.
http://www.flying-pig.co.uk/mechanisms/pages/cardan.html
Making an internal set of circular gears should be a simple matter for a gearshop.