I've sorted them out in my own mind into two buckets, which I call large-to-small and small-to-large.
In large-to-small, you start out with a large piece of fabric. Cut a slice through the middle of it, piece in a very skinny line of fabric, and sew it back together -- now you have two smaller areas with a line in between. Repeat -- now you have three or four smaller areas with lines in between. Repeat, repeat, repeat, ending up with ever-smaller areas and ever-greater complexity.
That's what we did on Day 1 of the workshop. After people got comfortable with the sewing technique, they concentrated on design. And after they had worked for a few hours on a composition, they were challenged to add a second color.
Here are some examples of what they came up with: