COMPLOT allows the user to interact with phase portraits of complex functions, also called domain colorings. Wikipedia provides an reasonable overview of what a phase portrait is and how it can be interpreted, but the best discription and exloration of these visualizations I know of is contained in Visual Complex Functions: An Introduction with Phase Portraits by Elias Wegert.
See it live on GitHub Pages: https://peterallenwebb.github.io/COMPLOT/#(z%2F2)%5E3%2B(z%2F3)%5E2-4*z#1