TeachScheme! 2002

  GENERAL RULE FOR ALL LAB SESSIONS:
    Some teachers have said they find it discouraging if they don't
    finish all the problems listed on the board, no matter how many
    times we tell them they're not expected to finish them all.  It
    seems to be a "checklist" mentality.  So, only put up 2-3
    problems on the board; give additional problems only to those
    done with the first few.

  Pragmatics: some syntax errors, some run-time errors

  Emphasize the syntax rules of Scheme.  Show them indentation.

  Assignments: 2.2.3, p11 [first function with 2 args]
               2.2.4 
    	       2.4.1, p14  [2.4 exercises explore errors -- important]
    	       2.4.2
    	       3.3.1, p28
    	       3.3.4  [challenging decomposition problem!] 
  
  PVD 2002:
  WATCH OUT for 3.3.4!  This is a *very hard* problem for most teachers.
  I mean seriously, shockingly hard.

  PVD 2002:
  Revised lab exercises get them to function composition earlier and
  have them work with error message exercises.  Postpone intro to
  teachpacks until later.

  PVD 2002: 
  For test cases, we used Steve's suggestion of 
    (cube 5) "should be 125"
  and it worked best of everything we've tried so far.