Before it got freezing cold out, Cookie and Ama were in the front yard together screaming and then listening for the echoes to bounce back off of the houses across the street, or wherever they were bouncing. I heard Cook explaining it to her very seriously. He said, "It's called an echo. Or sometimes it's called a lay-ee lay-ee hoo hoo." Apparently we learned about echoes from the goatherder marionette scene in The Sound of Music.