[Hume]

'The lifebox, the seashell and the soul' by Rudy Rucker.

http://www.rudyrucker.com/lifebox/

It has the same sort of feel as GEB, he riffs about cellular automata etc, its not too demanding while still giving enough to meditate on for a few days.

[baddox]

Bingo. I'm diving into the book sample and already enjoying it. Thanks.