There are certain things you notice when you first arrive in Sicily. The honey-coloured stone that seems to glow in the afternoon sun. Laundry dancing between narrow streets. Bougainvillea tumbling over ancient walls. And then, quite unexpectedly, the blue doors in Sicily that seem to be the dominant colour in coastal towns and villages. Not every door, of course, but enough of them that you begin to notice a pattern. Walk through the old quarters of Cefalù, Ortigia, Marzamemi, Sciacca or the winding streets of countless fishing villages, and blue begins appearing everywhere. Some doors are painted a deep cobalt. Others are faded turquoise after years beneath the Mediterranean sun.…