The PxrOSL Pattern node is a useful way to create and prototype OSL patterns from inside Maya. It's excellent for playing around with options and controls.
We only support OSL patterns (textures for shading) and not closures (materials).
You can see the source path under Compile and Reload buttons.
The naming here is very important.
If you fail to have the correct names you will get a warning and bad behavior.
Compile - Compile the current code to a .oso file for rendering