So I've recently gotten into finer watches (happy owner of a JS Watch Chrono and about to get an Epos Skeleton). When I was in Hong Kong I noticed a lot of the Patek fakes would have a sort of spring/tourbillon mechanism that was always spinning on the open heart portion of the watch. I really likes this mechanism and was wondering if there are any sub $3000 watches that feature an open heart mechanism that shows the spring moving back and forth (seemingly a few times a second). I really liked the action. Do all open hearts do this? Any specific models? I like the Frederique Constants, but not sure if their open hearts have action and movement. What is this called?