How Does a Butterfly Knife Work?

I guess I should mention there is always some kind of simple locking arrangement at the end of the handles away from the blade that keep the whole thing rigid when open.

As to 'how it works': real good, but more apt to be fumbled than a conventional switchblade. You hold one handle and flip the other handle and blade downward. Rotate the held handle and flip it back up. You are then holding the handle, with the blade open. I always thought the process were unnecessairly complicated, myself.