1) German invention
Found on
https://www.crosswordclues.com/clue/mengenlehreuhr
The Mengenlehreuhr (German for `Set Theory Clock`) or Berlin-Uhr (`Berlin Clock`) is the first public clock in the world that tells the time by means of illuminated, coloured fields, for which it entered the Guinness Book of Records upon its installation in 17 June 1975. Commissioned by the Senate of Berlin and designed by Dieter Binninger, th...
Found on
http://en.wikipedia.org/wiki/Mengenlehreuhr
No exact match found.
