f²(x₀) is the second iterate of x₀ under f.

Not long ago, it was difficult to produce photographs of tiny creatures with every part in focus.[…]A photo processing technique called focus stacking has changed that. Developed as a tool to electronically combine the sharpest bits of multiple digital images, focus stacking is a boon to biologists seeking full focus on a micron scale.

Makes being an egofag / dramallama a sort of risky thing when you give a rat's ass about protecting your online rep.

to set a good example