Day 10 is all about building those shoulder muscles, which are essential for most yoga poses from down dog to sun salutes.
Day 11 is the crow pose challenge, but don't worry if you can't quite get there yet, focus on how far you've come and how much of a difference you've noticed in both yourself and your practice
Day 12 is all about working towards the wheel pose. Like all challenges this isn't a one and done type of challenge. These stretches are going to need to be worked on and practiced til you can achieve wheel pose safely
Day 13 introduces you to inversions, so if you're working towards headstands then this is a great video for you to learn which areas of the body you need to tune up