A z-pinch squeezes a column of plasma with its own magnetic field. Squeeze it hard enough and the column does not stay a column: it pinches into a chain of bulges and necks, like a sausage string. That is the m=0 instability, and it is one of the oldest obstacles to confining plasma for fusion.

The figure is a simulation of that instability developing in a cylindrical equilibrium. It was the first figure et al. ever printed.

A galaxy so distant that its light has been travelling for most of the age of the universe cannot simply be measured; its properties have to be inferred. This figure is that inference laid bare. Each panel shows how strongly the data constrain one parameter of the galaxy's motion, and how those constraints trade off against each other.

The diagonal shows what is known about each quantity on its own. Everything below it shows which combinations remain possible together.