These are lobster-trap buoys, which lobstermen use to mark the location of their traps. They were leaning against the front of a tiny shop on Bearskin Neck in Rockport, which Zan can be seen standing in front of here.
And it’s well past my bedtime, and I’m deliriously tired, so I won’t waste your time or mine by trying to come up with some witty little anecdote that almost surely won’t make a shred of sense or be even remotely witty. It’s a nice picture. Let’s quit while we’re ahead, ok?