"sweat equity" is as cheap as you are willing to work ... after reading the article, spherical lenses are great in many many applications, there is still a pl

"sweat equity" is as cheap as you are willing to work ... after reading the article, spherical lenses are great in many many applications, there is still a place for aspheric optics one of which is large aperture telescopes you can reach without an orchard ladder or drone. the sibling comment on spinning fluids does lead the question; can the researchers vary the density of their neutral fluid (or polymer) to gradually vary the "local" forces shaping the lens