still trying to add the listeners, and getting errors:

Exception in thread "main" java.lang.StackOverflowError
	at eleven.graphics.Oval.setLocation(Oval.java:29)
	at eleven.graphics.Oval.<init>(Oval.java:18)
	at eleven.graphics.Avatar.changeLocationBy(Avatar.java:37)
	at eleven.graphics.Child.changeLocationBy(Child.java:42)
	at eleven.graphics.Child.changeLocationBy(Child.java:45) (this repeats almost forever)