Dan Ingalls showing smalltalk magic

• https://www.youtube.com/watch?v=NqKyHEJe9_w
• https://www.youtube.com/watch?v=4ki2AQvneD8
• https://www.youtube.com/watch?v=Ao9W93OxQ7U
• https://www.youtube.com/watch?v=if72CFsF_SY