A magnifying lens, or a picture reducer, without distortion! In order to explain you how it works, imagine gathering optical fibers in a cylinder, each fiber being perfectly parallel to its neighbors, and fused so that the whole forms a rigid rod. One side of this rod is stretched so that its diameter is reduced. You therefore obtain a cylinder with the same number of fibers on each side, but occupying different areas. As light is perfectly conducted through both lenses, a picture can be reduced or enlarged dot by dot, proportionally, without being distorted on the borders. Great!