It seems that people appreciate an increasingly wide range of avante-garde wristwatches.
Today’s invention is one such: consisting of a strip of gel on a paper substrate. This has gradations marked on it corresponding to the hours of the day.
A drop of dye is placed at a start-point on the strip at a known time in the morning. This moves along the strip at a known rate by the familiar process of chromotography. It passes the gradations and thus indicates the time.
This can be disposed of at the end of the day and a new strip watch wrapped around one’s wrist.