This tower in Oslo, down by the railway station, is called “Trafikanten”. It is actually both a clock and an art-installation. The red stripes of light visible in the colour version of the photo below is grouped into groups. Each of the group describes a weekday. If it is a Monday, the bottom set of lights are lit. On a Friday the full tower is lit. This photo was taken on a Wednesday. Guess how I can tell.
Wednesday in black and white
Wednesday in red