Put two iron pellets on a very thin, flexible fabric. Underneath the fabric, put a magnet so each pellet is stuck to one pole of the magnet through the fabric. Tug the magnet "down" in the third dimension, which will fold the fabric and move the pellets so that from their perspective (stuck to the 2D surface of the fabric) they're moving far away from each other. They also maintain a constant and very short distance in the third dimension, but they can't take advantage of it because I forgot to mention the fabric is impervious to them.