Maths buffs will love this clock. At first glance, it looks like a game of "Connect 4". Actually, "Red Fields" is a clock that shows the time by a combination of the binary system and place-value notation.
So, how do you know what time it is? It is entirely easy to read the time if you know how to go about it. The two top rows show the minutes in the binary system, such that the first row represents 15 minutes in the binary system and the second row counts the quarter hours that have elapsed. The two bottom rows show the hours in the place-value system. Meanwhile, one beep signals each hour on the hour.
Nonetheless, the clock has one disadvantage: If one of the illuminated squares stops working, the time turns topsy-turvy.
Illuminated Panel Clock, “Red Fields”, Time Design, Trier, pre-1989, Inv. 1995-165