etbgn...
The ETBGN (equalatral triangle based gap negotiator) is a prototype design for a robot gap crosser.
The drawing while not to scale does show how a cyclic motion can produce a shape shifting robot cabaple of navigating ditches drains etc.
by lenghting the arms(including triangle)  and increasing weight of main controller section
its possiable to build a bot able to cross a bigger gap.
c.mongke 2004
terraform robotics design  

email me if you have any ideas...
terraform@upnaway.com