Leave the final work open. As in, no set finished example. It should largely be their own interpretation. However, you should be careful to not have too much going on. I would have thought some examples shown of different forms of line. Lesson plan should consist of perhaps a SOW and you choose 1 lesson from this. Differentiation etc, and a detail of the actual lesson, a good breakdown. A lesson beginning and end, with the end reinforcing the point of the lesson rather than just a show and tell. Hope it goes well, this could be too late. And if this bl**dy helicopter stopped hovering over the house and nearby, I could have focused more and given some more details. options:- figurative work, depending on age, automatism, surrealists, op art etc, the list is pretty much endless.