Dusseldorf old town and weird window glasses.

Monday was total shopping day. We wandered all day at the city.
Toddlers did not protest this shopping tour, because they had enough bretzels and got a change to take a nap or jump in puddles. Weather was warm enought but it kept raining almost all day - quite heavily actually especially in the morning - felt like monsoon.
I found this weird window from the old town - glasses look like they are lenses of some kind.