Up a tree

During the inky darkness of a moon-deprived night, we heard the dog barking furiously at… something. Although we were disturbed by the barking, we were also pleased to know that the dog stands watch and promises to remove the legs of anyone who crosses the invisible line near his sleeping quarters. Good dog. The barking seemed incessant at first, and then he grew bored. The thrill was gone. But, t…