The Scratch Team have suggested that there should be a separate version of Scratch for college computer science students. We disagree. By following the principle of first class data, we can have a powerful Scratch with very few visible additions to the interface.
These ideas are implemented in BYOB 3, with first class lists and first class procedures. It is available at
This project is a severely abbreviated version of the full 20-minute propaganda film we prepared for the Scratch Team, which is too big to upload to the Scratch site. You can download it from