Concept Bikes & Bike Innovation - for better or worse

I think that was done in the early 80s when there was an attempt at automatic gear changes

Expanding chainrings have been around since the 19th Century

In 1901 he came on the four-speed proteon gear of the English Whippet. Here, the changes were made by the expansion of a split chain wheel. Partial reverse rotation of the pedals caused cams to open the two halves of the chain wheel and secure them in any one of the four positions by pawls.
http://cycling.ahands.org/bicycling/velocio.html