mpaddedAdepth2

W3C sample	WIRIS
	$\underset{x}{y} \underset{x}{y} \underset{x}{y} \underset{x}{y} \underset{x}{y} \underset{x}{y}$

<math xmlns="http://www.w3.org/1998/Math/MathML">
  <mrow>
    <munder>
      <mi>y</mi>
      <mi>x</mi>
    </munder>
    <munder>
      <mpadded depth="1.0height">
        <mi>y</mi>
      </mpadded>
      <mi>x</mi>
    </munder>
    <munder>
      <mpadded depth="3width">
        <mi>y</mi>
      </mpadded>
      <mi>x</mi>
    </munder>
    <munder>
      <mpadded depth="200%height">
        <mi>y</mi>
      </mpadded>
      <mi>x</mi>
    </munder>
    <munder>
      <mpadded depth="-1ex">
        <mi>y</mi>
      </mpadded>
      <mi>x</mi>
    </munder>
    <munder>
      <mpadded depth="10pt">
        <mi>y</mi>
      </mpadded>
      <mi>x</mi>
    </munder>
  </mrow>
</math>

Author: Robert Miner and Jeff Schaefer, Geometry Technologies