ed"></a-mixin>
        <a-mixin id="green" material="color: green"></a-mixin>
        <a-mixin id="blue" material="color: blue"></a-mixin>
        <a-mixin id="yellow" material="color: yellow"></a-mixin>
        <a-mixin id="sphere" geometry="primitive: sphere"></a-mixin>
      </a-assets>

      <a-entity position="0 0 4">
        <a-camera>
          <a-cursor></a-cursor>
        </a-camera>
      </a-entity>

      <a-entity id="shapes" position="0 0 -2">
        <a-entity id="blueCube"
                 