My apologies for creating confusion about the grades on lab 6. When I discussed grading standards with Melissa, I suggested that there be a small bonus for people whose implementation went well beyond the requirements. In the end, Melissa only gave this bonus (a single point) to a couple of people. Thus although in principle the lab had a maximum score of 21, hardly anyone got more than 20. The score was reported as X/21 -1 No extra credit (not an actual deduction) since from a bookkeeping standpoint, the lab was graded out of 21, and a single point was deducted from everyone except the tiny group that got the bonus. We could have worded this more clearly if we had said something like "You got X/20" for everyone, and "+1 for significant extra effort" for the couple of people who received that; the result would be exactly the same. Brian K