Poisson

The behavior of elastic materials is partially described by Poisson's ratio, which explains how the material changes shape when you stretch or squeeze it in one direction.

Most materials have a positive Poisson's ratio, which means squeezing them in one direction will make them wider and/or thicker in other directions.

Auxetics have a negative value of Poisson's ratio and do exactly the reverse.

Another way of expressing Poisson's ratio is that it describes the relationship between shape and volume when one of these changes.

As he prepared for the show to open in April, Di Donna gently blew on “Poisson” and it performed on cue, doing a delicately turning dance in response — a perfect bit of inspiration for art lovers who want to get in the swim of things this spring.