The Chromachron was invented in 1971 as a Colour-Time clock structure for the 1972 Olympic games. The name comes from Chroma which means colour, and Chronos which means time. It was invented by Tian Harlan who was an architect, engineer and artist. He wanted to make time-telling less rigid, as the smaller the increment we measure time in, the more we worry about wasting those increments. So the Chromachron was born in Switzerland with no hour, minute, or second hand so it can free us from the 'dictatorship of exact time' .
To tell the time, there is a black disc which rotates (1 full rotation in 12 hrs) and has a slice cut out which is one twelfth of the disc. The watch face is also split into 12 different colour slices, one for each hour. This means that to tell the time, you look at how the segment and colours interact - for example, it the segment shows around 2/3 yellow (12), and 1/3 orange (1), then it is about 12:40.
After the original (mechanical) release, over 100 different variants of watch and clock were released in the 80s (including this quartz model).
The colour/ hour combinations are:
Orange =1
Light Pink =2
Red =3
Dark Pink =4
Purple =5
Dark Blue =6
Green =7
Turquoise =8
Purple =9
White =10
Lilac =11
Yellow =12