02-13-2008, 07:23 PM
Those things are still in use. A few years ago I lived in the Appalachian mountains of Virginia when there was a coal miners' strike. To harass scabs going to the mines and the police escorting them, they strewed small caltrops all over the roads to flaten tires. They made them out of nails and called them "jackrocks," apparently for their resemblance to children's jacks.
Pecunia non olet