Here's a good way to show how the MAP block can be used by students to make interesting graphical effects such as simulating the "green screen" effect (i.e. to make specific colors - in a costume - transparent).
See the project below.
EDIT: I would not be able to make this project without using the following blocks, created and shared by KindDavid12 here.
Could you please add them to your (offical) pixels library?