It's really just a rearrangement of dirt: mopping. Before I mop there are spots and clumps of lord-knows-what on the tiles, and after I mop, it's all spread out evenly.
This is what I think when I mop the kitchen floor.
Other notable events:
1. the quince is blooming
(Should really be "another notable event", but I'm optimistic that there will be more, and I'll come back and add #2.)