<!DOCTYPE html>
<style>
rect, circle, ellipse {
  vector-effect: non-scaling-stroke;
  stroke: red;
  fill: red;
}
</style>
<svg width="100" height="200" style="background-color: lime">
  <!-- Neither of these should render. -->
  <rect x="10" y="20" width="0" height="10"/>
  <rect x="10" y="40" rx="1" width="0" height="10"/>
  <rect x="10" y="60" ry="1" width="0" height="10"/>
  <circle cx="10" cy="80" r="0"/>
  <ellipse cx="10" cy="100" rx="0" ry="5"/>
  <ellipse cx="10" cy="120" rx="5" ry="0"/>
</svg>