>>6184911

muh umbra, penumbra

>>6185447

thank you anon.

>>6185450

>>6185454

resorting to things your textbook taught you, eh anon?

>>6185518

you should be able to explain this then, ray diagram expert?

>>6185527

its just mental trickery replicable on paper and computer screens. zero experimental proof.

>>6185552

>>6185565