Guards
Where keyword
Pattern matching with where
Functions in where blocks
Let expressions
Let in list comprehensions
Case expressions
Hello recursion
The recursive maximum' function
The recursive replicate' function
The recursive take' function
The recursive reverse' function
The recursive repeat' function

Nice example of how to use 'recursion with no base case' to produce
infinite lists.
The recursive zip' function
The recursive elem' function
The recursive quicksort algorithm function
Higher-order functions
Curried and partially applied functions
Higher-order function's examples
Implementing zipWith'