Nice use of the word "frangible" in this otherwise disturbing Times article about deadly equestrian accidents:

The current debate over safety comes nine years after another rash of deaths shook the eventing community. In 1999, five British riders died in a matter of months and calls flooded in to make cross-country courses safer.

In response, British organizers developed frangible pins that can be inserted into certain fences to allow the rail to drop when a horse hits it. Although the pins have been available since 2001 and have been shown to be effective in helping to prevent rotational falls, they are used in only 4 percent of obstacles in Britain, where they are mandatory on certain fences. They are even scarcer in the United States.

Frangible means that when deformed it breaks into fragments--sort of the opposite of shatterproof. I never knew this word before but I like it a lot. It's as if they took fragile and tangible and mashed them up.

But I wonder if the article is leaving out some detail. I have a vague memory of watching an equestrian event on television and seeing rails easily knocked away when the horse didn't clear the jump. It seems like it would be terribly dangerous if they were firmly anchored to the fence. The simplest solution seems like having the rails rest in grooves cut into the sides of the fence. But perhaps that is the commonplace and the frangible pins are a further improvement. Going further, why not make the whole rail out of some cheap, flimsy and fragile material, so that it just gets obliterated when hit? I don't know what material would be optimal, but there must be something.

Bonus question: how do they make the "breakaway" bottles used for slapstick?