Via PaleoFuture.com: The design of this mobile dreadnaught, with its steel-tired, spoked wheels, suggests that its inventor may have been influenced by agricultural tractors or perhaps an amusement park Ferris wheel. The trench destroyer also embodies the common goal of military visionaries: maximum offensive power with total defensive security. http://www.paleofuture.com/blog/2011/1/21/the-trench-destroyer-1917.html