Play Ball!

I play this game where I throw my roundy thing across the room and then I crawl as fast as I can to get it. Once I pick up the roundy thing I throw it again and then crawl and pick it up again. I do this many times. Sometimes Mommy plays with me. She will roll the roundy thing on the ground and it will stop in front of me. I pick it up and throw it across the room. Mommy gets the roundy thing and rolls it to me again. I call this game Throw The Roundy Thing And Get It. Mommy calls this game Ball, but I don't know why.