The mat must be moved to the other side of the gym.
If a group is struggling, don't make them go back to the start, just have them pick up where they left off.
You can't touch the mat with hands after the teacher blows the whistle to start.
I did play this with 3rd-5th and it was not easy because we were using the atypical gym mats that most of us have. The mat this group was using in the GIF didn't fold and was extra wide.