I did this earlier on in the year for a good test to see where my group of students were at technically. You can see it's a pretty big scale of skill, which makes planning difficult but always fun!
We worked on 12x18 paper. I had them trace different shapes that I had previously cut and then draw at least three lines from one side to another breaking up the shapes. They used watercolors to paint each new shape that was created by the lines. Oil pastels were used for the shapes and lines to help keep them inside the shapes when they painted.