                 geometry="primitive: circle; radius: .2;
                           segments: 100; thetaStart: 0; thetaLength: 360">
        </a-mixin>
        <a-mixin id="cylinder"
                 geometry="primitive: cylinder; radius: 0.2; height: .5;
                           segmentsRadial: 50; segmentsHeight: 50;
                           openEnded: true; thetaStart: 0; thetaLength: 360">
        </a-mixin>
        <a-mixin id="ring"
                  geometry="primitive: ring; radiusInner: .3; ra