Fresnel lenses are neat
-F
@Felthry I had never heard of zone plates. My first thought was that "neater than Fresnel lenses" is a high bar to clear. Then I looked them up, and they did not disappoint.
@terrana Zone plates are *weird* and *neat*.
-F
@Felthry Most things taking advantage of diffraction are.
though zone plates are even neater
-F