Vega-Lite block example

https://cdnjs.cloudflare.com/ajax/libs/vega/3.0.2/vega.js

https://cdnjs.cloudflare.com/ajax/libs/vega-lite/2.0.0-rc3/vega-lite.js

https://cdnjs.cloudflare.com/ajax/libs/vega-embed/3.0.0-beta.19/vega-embed.js