<polymer-webgl-tutorial>
https://codelabs.developers.google.com/codelabs/polymer-webgl/index.html#1
Install the Polymer-CLI
First, make sure you have the Polymer CLI installed. Then run polymer serve to serve your application locally.
Viewing Your Application
$ polymer serve
Building Your Application
$ polymer build
This will create builds of your application in the build/ directory, optimized to be served in production. You can then serve the built versions by giving polymer serve a folder to serve from:
$ polymer serve build/default
Running Tests
$ polymer test
Your application is already set up to be tested via web-component-tester. Run polymer test to run your application's test suite locally.