Derivatives
A number of Scratch derivatives called Scratch Modifications have been created using the source code of Scratch version 1.4. These programs are a variation of Scratch that normally include a few extra "blocks" or changes to the GUI.
Some of them additionally introduce shifts in underlying approach to computing, such as Build Your Own Blocks or shorter BYOB, by not only allowing users to "build their own blocks", but featuring first class procedures (lambda), first class lists (including lists of lists), and first class truly object oriented sprites with prototyping inheritance, which are not part of Scratch. BYOB was developed by Jens Mönig with documentation provided by Brian Harvey from University of California, Berkeley and has been used to teach "The Beauty and Joy of Computing" introductory course in CS for non-CS-major students.
The source-code of Scratch and its derivatives are based on Squeak, which is based on Smalltalk-80.
Read more about this topic: Scratch (programming Language)