A Swedish mathematician skates on thin, black ice both as a thrilling pastime and a beautiful acoustic experience. Here’s how he does it (without falling in).
The idiom “skate on thin ice” usually means: danger—stop what you’re doing, or else. However, skating on thin, black ice is exactly what Swedish ice skating enthusiasts Henrik Trygg and Mårten Ajne love to do.
To hit the ice when it has just begun to freeze, in its most pristine, dangerously thin state, is the ultimate thrill in “wild ice skating,” or “Nordic skating.” It’s the “holy grail,” says Trygg.