Here is BJJ World champion Kyra Gracie showing a triangle choke:
Those who follow MMA know the Gracie name - Kyra is the greatgrandaugher of Carlos Gracie, and the niece of Renzo Gracie. I saw her train once in New York and she is totally awesome.
She is a one of the few girls in the Gracie family to have earned a blackbelt in BJJ.
And pretty hot too