This lesson is primarily directed at the Advanced Placement
Computer Science class which is taught using Java. 
BYOB/Scratch serves as an excellent scaffolding tool to visually
represent programming concepts.  Non AP classes which use
programming concepts such as loops and boolean (true/false)
expressions may also make use of this lesson.  Students should
already be familiar with concepts such as variables and
loops.  BYOB allows for the creation of several types of
custom built code blocks.  A predicate block is used to create
boolean expressions.