That was all there was to the dream: no plot, no characters, no role for myself, just one shot after another of these black-and-white Breton flags.
On Saturday (June 29), I started using a new textbook with a student of mine. The first page of the first unit included this illustration:
It's a black-and-white picture of the Greek flag -- literally black and white, even though the Greek flag is blue and white, and the other pictures I've included in the photo show that the illustrations use shades of gray, and that even coffee is portrayed as gray rather than black.
This version of the Greek flag obviously closely resembles the Breton flags I had been dreaming about: five black stripes, four white stripes, and a canton which is the Kroaz Du with the colors swapped.
This morning (June 30), I checked my email and found that a correspondent had sent me a photo of a moth with striking black-and-white markings:
The central black marking resembles both a cross and a heraldic ermine spot, suggesting both of the Breton flags.
Later today, I spotted this on the wall of a restaurant:
In both parts of the design, there are five black stripes, just as on the Gwenn ha Du.
Update: After lunch, I went to a used bookstore and found a book about Ireland (a Celtic nation, like Brittany) shelved next to one with a zebra on the cover.
Update 2: Forgot to include this photo, taken on the street the same day. Of course it had to be five black noodles hanging from the chopstick-flagpole: