CSC153, Class 30: Discussion of Exam 2

Admin:
* Surprise!  Exam 2 is graded.
* I hate purgatory/heck/whateveryacallit week.
* Why is it that whenever I return an exam, Chase misses class?

Overview:
* Some general problems
* Problem 1: Cloning
* Problem 2: Less-Than?
* Problem 3: Section
* Problem 4: Not a Problem
* Philosophy of Objects

See exam2.scm for lots of details