盆 ("pen", tray) 栽 ("zai", planting) - an ancient Chinese art of forming trees and landscapes in miniature, also called penjing and an ancestor of the Japanese art of bonsai. Penzai is a JAX library for writing models as legible, functional pytree data structures, along with tools for visualizing, modifying, and analyzing them. Penzai focuses on making it easy to do stuff with models after they hav