Abstract: A device for effecting relative motion of movable components of a product within a closed sales display package translates a force exerted in one direction so that the force is applied in a second direction through buckling of a motion spring. The motion spring is two-dimensional, i.e., flat, and is oriented so that its flat surfaces face the direction of motion and so that its top and bottom edges are secured to opposite sides of a sales package. Pressure that is exerted vertically on the top and bottom edges of the spring causes the spring to buckle about a horizontal axis, thereby deflecting the flat surface of the spring in a horizontal direction that is perpendicular to both the vertical direction of force and the horizontal buckling axis. The motion spring is secured at its top and bottom vertical edges to the front and back, respectively, of the sales package. When the spring is to be used in conjunction with the rotatable toothbrush of U.S. Pat. Nos.