If Ryan is showing one boy something, he can be sure that within seconds that other boy will be joining them, as well. And if Lila sees both her brothers doing something, she's not about to be left out.
Especially if the activity involves the iPad. The boys don't use the iPad much, because when they do they get sucked in and it's not a lot of fun for anyone when it's time to stop. So using the iPad is a treat--especially when Ryan pulls up the app that allows them to create songs together. (Do I know what it's called? Nope.)
This particular day, each child laid down their own track, then Ryan overlapped them to create a song that was, well, interesting.
I mostly enjoy watching their faces.