Oddly enough, the gait described in the books, particularly "City of Gold and Lead" was a whirling motion. I've seen, somewhere, an attempt to diagram that -- I am fairly sure it was within the pages of "Barlowe's Guide to Extra-Terrestrials" (the great book of paintings of famous fictional aliens by Wayne Barlowe). http://www.amazon.com/Barlowes-Guide-Extraterrestrials-Science-Literature/dp/0894803247 I see that the BBC design used in tripods was quite different, however, and extended to the tripods themselves; instead of three balanced legs they seem to have two fore and one aft. Every film project I've read about that tried to visualize tripodal motion, whether John Christopher's or H.G. Wells's, came to the conclusion that a true tripodal gait was extremely difficult to visualize and inevitably looked stupid. At least that is the tenor of any commentary I've read. For a good gait for the two fore and one aft structure, however....you might want to take a look at a couple of creatures that have evolved to use it. There are some lovely creatures that drag themselves forward on two huge columnar arms in the Karl Sims movie "Evolved Virtual Creatures" http://www.genarts.com/karl/evolved-virtual-creatures.html And similar gaits exist in some of the species of the rather later "Spore," a game designed by Will Wright. http://en.wikipedia.org/wiki/Spore_%28video_game%29 In the case of "Spore" the game engine figures out a gait for a creature you design -- it could be a useful tool for looking at motion possibilities.