They’ve been … grinding away at the stairs in this building for the last few days. The house is from the late 1800s, and (apparently unusually) the tiles in the stairwell are made from concrete, not ceramics. So they’re porous, and grow ever-more dirty over the years?
I’m not an expert. I didn’t know that this was a thing.
So they’re “cleaning” the tiles (i.e., taking off the top layer) with a grinding thingie.
But I came home now and looked at the tiles and though “well, that was a lot of noise for no change at all”, and then I noticed that they hadn’t done the corners yet:
I guess… that’s… a slight difference? No?
I’m so observant.