https://github.com/davepinch/pinchy.cc/blob/master/content/topics/weather/hurricane-katrina/nws-bulletin/06.md
Dragonflies have compound eyes, which consist of a number of smaller visual units. While houseflies have 6000 compound eyes, dragonflies have up to 30,000. These units present the dragonfly with one picture, not 30,000 little ones.