Scheme practice problems:

1. In Prolog we wrote a predicate that reversed the elements of a list.
Write this in Scheme.

2. There is a built-in function in Scheme to test for membership of an 
element in a list. Write a Scheme function memberOf(x ys) to do this task.
(memberOf(2 '(1 4 (2 3))) should return false as it should only check
the top level elements of the list ys (shallow recursion).

3. Write a deeply recursive funtion on lists that counts the number of 
numbers in a heterogneous list of elements that are numbers and atoms.
That is, on the list ((1) 2 sam (larry 5)) your function should return 3 as the
value calculated; note that this list has 4 top-level elements.

4. Makeup your own higher order function that takes a function as its argument.
Demonstrate examples of function application and write 1-3 sentences about what your 
function calculates.