I've always really liked these inflatable tennis courts, ever since one appeared in the park behind my house in Northampton, in the 1980s. Not because they're a boon to tennis players in winter, but because of the shape. The German architect Frei Otto was the original master of tensile and inflatable structures but I don't know if he liked tennis. I'm sure he would have been pleased with this photo, though. I have been trying to get an elegant shot of these for a few weeks now (some smaller examples below) but today the light was right, creating a remarkable translucent pair of tennis-enabling domes.