Dahl artist Quentin Blake is nominated in the six and under section for Angelica Sprocket's Pockets.

BBC: David Walliams up for Roald Dahl award

On the back wheel: the small sprocket is top gear, the large sprocket is bottom.

BBC: Sport

Cycling did not appeal to the masses until the introduction of the pneumatic safety bicycle with a chain and sprocket drive (the prototype of the modern design).

FORBES: A Comic Look At The 1890s Bicycle Boom

In the early 1990s its engineers figured out how to squeeze a digital soundtrack onto a piece of film without losing the analog soundtrack, by putting the digital track into the spaces between the sprocket holes on a piece of film.

FORBES: Technology

In their bid to simplify loading 35mm film, Kodak, Fuji and other photographic firms squared off the 35mm roll's lead-in tab so a modern SLR's motor-driven loading mechanism could grab the film's sprocket holes and wind it automatically onto the take-up spool.

ECONOMIST: A die-hard analog photographer goes digital