This is another bizzare musical innovation from your friend and mine, Pat Metheny. I'd kill for a guitar like this, but I'd have a hell of a time finding a case for it.

I believe the 42-string Pikasso guitar was designed by Linda Manzer per Metheny's request for a guitar with as many strings as possible.

If I recall correctly, the strings were organized thusly (looking at the guitar as someone holds it facing you):

1-8: 8-string bass strings running from the upper left-hand corner of the body diagonally to a bridge near the bottom of the guitar. These are sympathetic strings, that ring only because of resonance. They are never played directly.
9-12: 4 bass strings running parallel to and below the first 8 strings. Also sympathetic.
13-24: Twelve strings running from a large head at the top right of the body, diagonally across a small soundhole and continuing over the large "normal" soundhole.
25-36: Another twelve strings running from another large head, perpendicular to the "normal" neck, and across the smaller soundhole.
37-42: Six ordinary guitar strings, found just where you'd expect them to be. These are the only strings to be fretted.
This guitar really does look like something Picasso would have dreamed up. I believe there was also a Pikasso II, made for <someone else>, the difference being that the Pikasso I had active electronics and the II was completely acoustic.
As soon as I finished writing my entire WU from memory, I decided to actually do some research and found a detailed description of the guitar at Manzer's website: lmodels.db&var3=Custom%20Design&wfskudata=2931-15

Seems my memory is pretty good! This is an incredible instrument that must be seen to be believed. (You might not believe it was a guitar if you heard it!)