Dried artichoke flowers releasing their silky seeds.
As for the wireless thermostat that came with the new boiler, as happens often, writing about it has made me into a liar. We waited and waited on Wednesday for the inevitable "fail" only to be disappointed. Or, not disappointed. There was no failure at the predicted time nor at any other time. My neat little theory fell apart. I have only one explanation: I had moved the remote unit to a new location. We suspect that the signal may have been weaker where we had originally put the unit. Now it's in a more open location. If that's the case, it's a very sensitive little box.
We still think that the receiver, which is attached to the boiler itself, is in the wrong place. It's attached to the back side of the boiler, requiring that any signal pass through the boiler itself to be received. The documentation says that metal objects can block the signal. Already, the floor through which the signal passes contains steel beams. Strike one. There is also a reinforced concrete bearing wall in the way. Strike two. Then the signal has to pass through the boiler itself, a metal box filled with metal parts. Strike three. We may ask the installer to relocate the receiver unit to higher up on the wall behind the boiler to eliminate that obstacle. Stay tuned.