Wheels within wheels

Re: More Alan Kay notice
Spotted in Smalltalk Tidbits, Industry Rants :
But late-bound has some deeper and more profound properties that include abilities to actually change the both the structure and metastructure of the language itself. Thus an important new idea can be assimilated into the constantly evolving process that is the system.

Another aspect of late-binding is the ability to change one's mind about already instantiated structures that are already doing work. These can be changed automatically on the fly without harming the work they are already doing.