There was a dog at the beach barking into space. On the other side of the river a barge heard the barking and returned it. The dog kept barking. The dog especially liked long peels of barking so that the reflected dog’s voice mixed with his.
The person with the dog kept telling the dog to be quiet with voice and hand gestures. It would work for an instant. I suppose it would take a long time to convince a dog that a reflection is not so interesting. Boredom will come on its own. In the meantime, this dog brought me delight.