Anyone know how to use "identicons" with Ruby on Rails?

An "identicon" is a small 9-block image generated using hashed data,
like that of an IP address to visually identify users quickly while
still preserving user privacy.

http://www.docuverse.com/blog/donpark/2007/01/18/visual-security-9-block-ip-identification

There seems to be a couple of variations for PHP, Python etc... is
there anything like this pre-packaged for Ruby on Rails? I have
looked and been unable to find anything.

http://en.wikipedia.org/wiki/Identicon

There isn't, but it'd make a neat plugin for interested folks.