<?xml version="1.0" standalone="yes"?>
<svg xmlns="http://www.w3.org/Graphics/SVG/svg-19990412.dtd" width="4in" height="3in">
  <desc>This example uses the switch element to provide a 
  fallback graphical representation of an equation, if 
  MathML is not supported.
  </desc>
  <switch>
    <foreignobject system-required="http://www.w3.org/TR/REC-MathML-19980407" width="100" height="50"/>
    <g>
      <rect style="fill: red"/>
      <text>Formula goes here</text>
    </g>
  </switch>
</svg>