I build a self-referential system, then tried to copy only parts. I need
to step back and adjust my approach.
'Toy_private_deepCopyValue' and 'Toy_private_deepCopyScope' need to be
ripped out, and I need to simply accept there will be only one instance
of 'Toy_Bucket' that isn't freed until the top-level VM is.
I need an hour's break before I'll tackle this again.
See #163