Stuttgart-based designer Stephan Henrich describes his firm's specialty as "Robotic-design and architecture in physical realisation and speculation." Given that description, perhaps it's unsurprising that his concept for an all-wheel-drive bike is pretty outside-of-the-box:
"The INFINITY beach and city cruiser is driven by a revolutionary monotyre-clip chain construction that forms automatically a temporary rim in the wheel area and a dented beltdrive in the bike's center area. This monotyre is propulsed by a central dented wheel getting its force by a crank over a short chain and a 8-speed gearbox. This combination makes 'allwheel-drive' possible. The tyreguide rails in the wheel areas are fully suspended (parallelogram to maintain the rim guidance)."