Exercise 1: do-a-thing
Exercise 2: spiff
Exercise 3: cutify
Exercise 4: spiff-destructuring
Exercise 5: width, height
Exercise 6: square
Exercise 7: area
Exercise 8: contains-point?
Exercise 9: contains-rectangle?
Exercise 10: title-length
Exercise 11: author-count
Exercise 12: multiple-authors?
Exercise 13: add-author
Exercise 14: alive?
Exercise 15: element-lengths