CHROMACHRON TIAN HARLAN 1973
(kris)Tian Harlan is a German designer/artist known for akward ideas. His "Chromachron" / "Colour-Time" concept led to the creation of a timepiece for people that do not need to be on time ever :) Pieter Doensen's site describes this as the "anti-stress" watch as it will never show you the exact time. The dial consists of twelve colorful triangles covered with a rotating disc. Each color is equal to one hour so once the disc covers half of two colors the time will be in the middle of those two colors. Second picture below reads 3:30. With some experience reading the time becomes pretty easy as it's a matter of getting used to the layout.
A whole bunch of different shapes and sizes were made and the one shown here comes from the earliest period of 1973-78 with mechanical AS/ST Swiss movements signed by Gisiger-Greder. Even Pierre Cardin had these made with his logo. Later versions were fitted with quartz movements and to my surprise such watches in black round cases are still made and sold today for a couple hundred Euros. The Chromachron should be considered as a design-focused timepiece, it is also a watch to some extent but that is an additional byproduct :)
Keywords: chromachron, colour-time, tian harlan, pierre cardin
Market value: 75-300$ (condition, version, brand, box)