On three occasions in my life I've had a migraine. I wasn't sure until reading this article today today, because they've never been accompanied by any kind of

On three occasions in my life I've had a migraine. I wasn't sure until reading this article today today, because they've never been accompanied by any kind of pain—just the bizarre disturbance of my field of vision being cut up into little scintillating triangles, gradually spreading over my field of vision until I could not read, then after 45 minutes or so fading away. The first time it happened was more than two decades ago, after a long summertime bike ride, and I thought the effect was a more severe form of the sort of mild visual pulsation that can be caused by depleting one's electrolytes by sweating out a lot of salt and only drinking water. Only much more recently did it happen again, and migraine was mooted as a potential cause—but until I saw these drawings I was pretty skeptical. Now I'm sure of it.