I'm brazilian and had one of these in my house my entire life. They are not dangerous as it sounds. BUT, gas showers are (please translate to you language):
> (Reminder: When I say “regular expression” here I obviously mean it in the programmer sense, not the formal language theory sense.)
Once I read an article where the autor recomended using "regular expression" meaning the formal theory and "regex" to point out the (more powerfull) implementation. I think it's a good way to provide a common vocabulary.