Accidentally ran across a bike show last Summer and took a few pics. Helps put into perspective how many times the wheel has been reinvented so to speak. Besides the obvious continuity of some engineering (chain driven “safety” bikes/ fixed gears, a hobby horse etc) many designs have been resurrected after a long enough period; lost to history or when an expired patent became public or if newer technology and materials dictate feasibility. Belt drives have made a come back with intro of better belt materials, the shaft drive recently resurfaced (100+ years on that old design but doesn’t seem to have “stuck” even the 2nd-or 3rd?-go round) as well as the Alenax chain lever (see earlier versions pictured) – and monocoque, recumbent trikes etc have all been given a thorough revision since their invention. The chain tensioned/ guided by what looks like steel housing/ conduit was certainly new to me. (If you thought finding the right bcd chainring for an old crank was difficult imagine being stuck trying to replace this likely patented-to-the-hilt chain assembly). Additionally the green Pedersen bike with hammock style saddle seems to be a combination of a Slingshot and Softride for suspension (http://www.pedersenbicycles.com/history.htm).