="aboveUnknown" width="10px" height="30px" style="background: purple"
></mspace><mspace id="belowUnknown" width="10px" depth="30px" style="background: blue"></mspace></unknown></math>
    <math><mtable><mtr><mtd><mspace id="aboveMtd" width="10px" height="30px" style="background: purple"
></mspace><mspace id="belowMtd" width="10px" depth="30px" style="background: blue"></mspace></mtd></mtr></mtable></math>
    <math><none><mspace id="aboveNone" width="10px" height="30px" style="background: purple"></mspace><