On the first sketch, Tim told us to draw not the figure in front of us, but just anything; a scribble, blob, whatever. This is what I drew (it's horrendous HA): - This is meant to represent the absence of someone.
On the second sketch, Tim told us to fill the canvas with charcoal, then rub out anything that resembled a figure. This is mine: - This is meant to represent the presence of someone or something. As if they've left the room.
Even though it was fun, I've come to the conclusion that I am awful at it!!!!