Charcoal on white paper. The instruction was to just draw the shadow and light, no midtones.

Charcoal on chipboard and oil paint. The process was to draw first with the charcoal, then spray it with fixative so we could paint over the top of it. 

Full value drawing.

Other medium drawing. I chose to draw this with my wacom tablet and laptop in the classroom.

White charcoal on dark paper. The instruction (similar to the white on dark drawing) was to draw the highlights and shadows, no midtones.