I continue to be fascinated by the interplay between the constraints of the physical world and the opportunities of plotting that can afford. I just came across an example today. My hero, Frederick, escapes his keepers in the company of a few friends, to join up with some better-armed and more experienced allies. He escapes by boat, from Palermo to the nearest island, which is Ustica. I was thinking about at what level I would narrate that journey, so of course I needed to know how far is the island, but even more I needed to know how long Fritz & Friends (sounds like a cartoon, doesn't it?) would be in their small sailboat. I also needed to know about their pursuit--because of course his keepers would come after him--and specifically when the pursuit might overtake him, which meant knowing about sailboats and galleys. That research unexpectedly gave me a plot point. There's no tension in having Fritz simply sail over and get on a bigger boat and sail away. That pursuit needs to get close; perilously close. But there's precious little difference in the speed of sailing vessels, unless one or the other can pull off some trick or get lucky. I went for the trick. Some miles east of the isolated Ustica is a chain of islands known as the Lipari Islands. So, Fritz reaches his allies, but they're closely pursued. More ships have been mobilized and it looks like they're going to be caught. Henry (the ally) unexpectedly sails more or less into the teeth of the enemy, into the Lipari Islands. But he has an ace to play: a wind wizard. Conjuring up a strong following wind helps hero and antagonist alike, so that's no good. Henry uses the islands and the winds to feed his own sails while leaving the pursuit becalmed in the lee. And, scene. OK, so maybe I could have thought all that up on my own. But the real-world logistics of sailing gave me the inspiration. More on point, what started as research into a straightforward question of sailing physics led to plotting, and introduced a wizard onto the ship. Kewl.