The spherical aberration of the same lens is demonstrated with the files PCLENS.OPT, PCLENS.RAY, and GLASS.MED. Load each one and run Layout. You will see a fan of rays, all of the same wavelength now, passing through the lens at different heights. With Plot you can inspect the screen to see where they fall. Careful editing of the ray table will allow you to follow pairs of rays through the system and observe their positions on the screen. Again, Auto will move the screen to a point of best focus of a pair of rays.