- testing programs
	- computer errors CAN kill people
	- look up Terac on Google
	- so test your programs well!
	- could also look into mutation analysis

- study the comments on Asst. 2
	- these were the majority of class discussion today

- cons = construc
- car = left of pair or first of list
- cdr = right of pair or rest of list

- historical naming reason
	- pairs of adjacent memory locations
	- left one was a pointer to left part of pair
	- right one was a pointer to right part of pair
	- when moved into working register, left was in address register, and right was in decrement register
	- hence, Contents of Address Register
	- Contents of Decrement Register

- null? tests for the empty list
- in Scheme, (not (pair? ...)) is what you would use for atom?
	- ideological reason will be explained on Monday

- cadr, caddr
	- second, third, etc elements of a list
	- going by the MIT Scheme manual, there appears to be only a finite number of these procedures
	- however, there is a procedure to give the k'th element of a list
	- also easy to write recursively