I discovered this last week when I was at MIL's place to pick up Charlotte. Nobody taught her this or asked her to do this, I also have no idea what triggered her to do this. It is real funny but yet her concentration and determination in getting it done is very impressive.
She can do this with either her right or left foot and when she managed to pick up the object she will say "Nah!".
I didn't have my camera with me that day and so it was captured with my phone camera. The screen is real small and that's why I only get a picture of her feet. I will try to get a better video clip next time ;)