1/2 turn to double tuck
The Fan is one of the newest dismounts in the code of points, and came about…sort of by accident? In 2017, the code of points upgraded a similar dismount, the front 1/2 into back tuck, from a D to an E. So then people were like, “Hey, we should start doing that dismount.” And then the WTC went, “Boo. I hate you and Fan Yilin in particular, so this is a different skill that’s worse, and you’re going to have to submit separately.”
Thus, the Fan dismount was born at worlds in 2017, then valued at a D. The WTC later decided they hated this dismount so much that it would become a C starting in 2022.