Move the mouse around, and the other 3 mice will mirror the movement in all 4 quadrants. Click to put pen down and draw.
Playing around with 2.0 some more, this time just getting used to new script interface and trying out vector graphics for the mice image thing that looked cool but was way too big. Yay no jagged edges with the change size command! Drawing with this is awesome, you get perfect horizontal and vertical symmetry no matter what you do.