An apparatus including: an intermediate chassis configured to move in at least a first direction and configured to define a reaction surface; a movable chassis configured to move in at least a second direction orthogonal to the first direction and configured to define a follower wherein the reaction surface and follower interact to convert movement of the intermediate chassis and reaction surface in the first direction to movement of the follower and movable chassis in the second direction. Also, an apparatus including a first movable housing portion having side faces including one or more interface components; and a second housing portion; wherein the first movable housing portion is movable relative to the second housing portion between a compact configuration in which the one or more interface components are obscured by the second housing portion and an expanded configuration in which the one or more interface components are exposed.