Llull, Bruno, Borges, and the fourth dimension

Charles Hinton worked on visualizing the fourth dimension.  There are some interesting connections between his techniques and and other visualization methods like the Ars Memoria. (Ramon Llull, you'll recall, invented a way of recombining words to make new ideas called the Ars Combinitorica, which influenced Leibniz's grand AI project. Jorge Borges, the scholar and author, commented on Llull and on ontologies.)  Check out the links below.

http://www.waggish.org/2010/charles-hinton/

http://ideafoundlings.blogspot.com/2009/10/maelstroms-from-renaissance.html

http://higherspace.wordpress.com/2010/03/09/borges-on-hinton/

Also, Boole's daughter (I discuss both her parents in the book) was adept at visualizing the fourth dimension.
http://www.agnesscott.edu/lriddle/women/stott.htm