from “is it directional? how cheap could you make a big antenna?” i am not a radio engineer. satellite dishes use the reflection of metal to focus signals onto a receptor. the curved shape behind them is analogous to the lens of the eye, bending the radiation differently depending on what part it strikes. usually they are designed to focus parallel radiation from an effectively infinitely distant source in outer space (with a parabolic shape). they can instead be designed to focus emission from a specific arbitrarily located relative fixed point at a specific arbitrary distance (with a spherical shape). the two curves are physically similar but focus differently. they could also surface soft or hinged material so as to change how they focus live. this would be analogous to how the muscles of the eye reshape the lens so as to focus near or far. similarly you could put an array of sensors at the receptor rather than a single one. high-end radio telescopes do this, outputting a small count of pixels rather than a single signal. these are analogous to the retina, the array of receptors in the back of the eye. once you put two of them next to each other on gymbals, the stereoscopic vision you are making analogy to is possibly what radio astronomers do to triangulate distances from two different locations — but if your reflectir is bending itself to focus on something near rather than far you are doing something a little different. […]