Abstract: The present invention provides a movement output apparatus for controllably moving a movement output means in at least two spatial dimensions, the apparatus including: a cog means with a first diameter; a ring with a track formed on an inner surface of the ring, the track having a second diameter which is larger than the first diameter; wherein: the cog means is rotatable by first driving means; the ring is rotatable by second driving means; the cog means is arranged to move, in use, along the track; and the movement output means is attached to the cog means, whereby, in use, movement of the cog means effects movement of the movement output means, and the movement of the movement output means is controllable by control of the first and second driving means to produce substantially linear movement of the movement output means to produce substantially linear movement of the movement output means.