One of the areas of the national curriculum that we should be introducing students to is RECURSION.
This is an excellent activity to introduce that concept in a visual way with a simple task to create a fractal tree in Scratch programming.
This activity I had a learning observation on. I had my students work in small groups to try and complete the main activity together. When they finished this, they were to research other fractal activities on-line and see what they could create.
Students really enjoyed this activity at the end of the Scratch topic to introduce a very complex topic that is not part of GCSE, but that appears again at IB level and A level.
I expect students to learn that recursion is a complex rule that simplifies programs, but is very difficult to understand and it is a function that uses itself to solve a problem.