Thank you so much! That was exactly what I was looking for. Your solution worked perfectly. Two seconds to adjust the horizontal coordinates of the layer after the flip, is preferable to 2 hours of trying to recreate something. There are a lot of applications I have in mind for this, and it will be ...

If I've created a bone layer and animated it, is there a way to reverse the horizontal orientation of the bones? That's to say, if I've made an animation that goes from left to right, can I make the animation go from right to left without having to start over from scratch? Thanks in advance.