title: AFRAME.registerGeometry Doc Example Throwing Errors
body: <p>The example code at the end of the docs under "Register A Custom Geometry":
  <a href="https://aframe.io/docs/0.4.0/components/geometry.html#register-a-custom-geometry" rel="nofollow noreferrer">https://aframe.io/docs/0.4.0/components/geometry.html#register-a-custom-geometry</a>
  throws a "core:schema:warn" error. </p>
  
  <p>Is anyone successfully registering custom geometries in A-Frame or is this something that's currently broken A-Frame itself?</p>