I have a document that describes a model of a 4-dimensional Rubik's Cube
(3x3x3x3) and a program that implements the model. The document is a
stand-alone that executes on a Macintosh and the implementation of the
model runs on a Mac as well.
This paper/program is based on an unpublished paper by Harry Kamack and
Tom Keene that was referenced in Hofstader's '82 SA column.
I'll be more than happy to share them with any interested parties - let
me know your interest. Anyone with a site on the Web who would like me
to upload the files please let me know. The document is 305K bytes, the
program is 197K bytes.