I was watching a TV programme about Brazil. Mostly Samba, of course. And Bossa Nova. Then they showed some musicians from the rural northeast. The line up was accordion, TRIANGLE (!) and big drum.
This was Forro (pr. faw-HAW ). I'd never seen any other musical form which used a big triangle played cajun style, but I bet regulars can tell me more.
Link 1 takes you a NYT story and multimedia slide show on Forro music. Although the cultures grew up separately, the parallels to SW Louisiana music and dance are interesting.