Or rather, cobblestones in what has become known as the Florentine (or Belgium) pattern:
No strange sight to anyone living in Germany, France, or Switzerland – but I‘ve often wondered why people would take time to do this? I have not been able to find any documentation – but my own personal guess, based on other things I‘ve read when studying this, is that a non linear pattern like this holds up especially well against regular linear traffic, such as would be caused by horses and carriages.
I took this snap in the amazing city of St. Gallen in Eastern Switzerland.