Sounds like Ming-Jen Wang patented Ted Nelson's ZigZag structure (http://xanadu.com/zigzag/) which is prior art (fully described at least by 1999-see http://himalia.it.jyu.fi/ffdoc/fenfire/history/Milestones.ge...) and quite possibly patented by Ted Nelson as well (http://lambda-the-ultimate.org/node/233#comment-1715). And I'm only familiar with ZigZag because of my interest in Ted Nelson's work, otherwise, it doesn't seem to have gone anywhere.