CSC151 2007S, Class 12: Recursion, Revisited

Admin:
* Due: HW 6
* Assigned: HW 7
* No new reading!
* Yes, I do intend to get grading done this weekend.  
  I apologize for the delay.

Overview:
* Q&A.
* Lab.
* Optional topics: Scheme's Evaluation Strategy; Another Example.