a: (refcount=3, is_ref=0)string '419796578' (length=9) a: (refcount=2, is_ref=0)string '419796578' (length=9) a: (refcount=1, is_ref=0)string '419796578' (length=9) a: (refcount=0, is_ref=0)null There are other challenges with garbage collection, like detecting cycles, but for this article, having a basic level of understanding of reference counting is enough. Programming languages are implemented