Our solution

So after spending the day yesterday, rescuing Lily after rolling/scooting off her activity mat. We decided to do this last night. I purposely placed her activity mat off to the side to try to keep her protected from the active 3 year old, so it made me a little nervous doing this, but Cecilia did really well. And the white blanket, did a great job of giving Cecilia a visual to slow down in that area!

Playing with daddy and Cecilia.

But she still managed to get herself off of it!