We were limited to six drawing implements - three dry and three wet. These were given a number - 1 to 6. The appropriate implement was used when the number was called out, taking away the need for decision-making and rather liberating.
The model posed for a series of short poses (2, 3 or 4 minutes) and one or two longer one - (10, 15 minutes), changing position after each one. Some drawings were done on top of previous one.