Combinations of lenses with different curvatures about x and y (often just cylindrical surfaces) can be used to magnify an image along the x- or y-axis, as is shown in this classic 2x afocal anamorphic attachment by Hallock Smith.
This is a fairly simple example of a design form used in cinematography. I’ve designed much more complex anamorphic systems with zoom capability. Anamorphic optics can also be used to create a wide field of view for virtual and augmented reality applications.
