Abstract: For motion transformation an apparatus includes a key and a plunger. The key moves along a first axis in a linear key displacement direction and along the first axis in a linear key return direction that is opposite the key displacement direction. The key includes a motivating arm on a distal end. The motivating arm includes a displacement cam surface disposed on a ventral side of the motivating arm and a return cam surface disposed on a dorsal side of the motivating arm. The plunger moves along a second axis. The plunger includes a displacement interface that is motivated by the displacement cam surface in response to the key moving in the key displacement direction to motivate the plunger in a plunger displacement direction. The plunger further includes a return interface.