the.com/lens
a curved sliver of glass that bends light into everything you've ever seen clearly
named afterthe lentil, which it resembles in shape
in your eyeflips every image upside-down before your brain corrects it
oldest knownpolished rock crystal from 750 BC Assyria
liquid versionsquid and fish eyes use graded-density gradient lenses
focal trickthicker glass bends light harder and shortens focus