It's becauase the argument passed to the chr() method is out of the range. Want to learn more Python for Data Science? Head over to DataCamp and try their free Python Tutorial
The second product used in this project is Liquitex pouring medium. This is a low viscosity (very fluid), clear, and high gloss acrylic medium. It is about the consistency of warm honey; quite sticky also. It can ben used with your regular heavy body paint to make them flow easier, and create cool dripping effects.
As mediums for painting go, concrete is not one of the better ones. It transfers moisture from the ground or surrounding dirt, and it breathes and sucks up paint like a kid with a soda. Concrete requires special paints that contain binders that contract and expand right along with the surface.