xkcd #2991: Beamsplitters
Beamsplitters
Under quantum tax law, photons sent through a beamsplitter don't actually choose which path they took, or incur a tax burden, until their wavefunction collapses when the power is sold.
Are beam splitters the main component in telescopes? It's funny, but probably way more relatable to an astronomer, or someone who does optics stuff with telescopes.
Did you read the explainxkcd link?
No, I didn't realize there was one. Thanks! Totally missed the link
Pentaprisms from SLR cameras have a similar but slightly different function, so personally as an amateur photographer who doesn't use a SLR but learned about em, I think it's pretty easy for photographers who used such tech to relate.