My current largest piece, a mosaic of Benedict Cumberbatch! He is the actor for Sherlock, Khan from Star Trek, Warhorse, and Parade's End. The mosaic is made of only the black plate for the background, and 1x1 clear bricks. The shades come from stacking multiple clear bricks on top of one another to get different shades of grey.
To give you an idea of size, here is me standing next to the piece. It is roughly 3 feet tall.
Hope you enjoy him as much as I have had building him.