I was in Lawrence Marvit's design class a couple of weeks ago and it was hard on the brains. There we dealt with value (in grayscale), space, texture and sculptural form.
One of the first assignments was to sculpt a sea-monster with pencil or photoshop making it as dynamic as we could.
Then we did a romantic scene in a junkyard, building up an atmospheric feel by stacking values and to make it interesting spatially.
Lines was actually kind of a no no in this assignment but I find it really hard working with only shapes and no borders.
And here's the final version.