own> in MathML Core -->
    <math><menclose notation="box"><mspace id="aboveMenclose" width="10px" height="30px" style="background: purple"
></mspace><mspace id="belowMenclose" width="10px" depth="30px" style="background: blue"></mspace></menclose></math>
    <math><mpadded lspace="10px"><mspace id="aboveMpadded" width="10px" height="30px" style="background: purple"
></mspace><mspace id="belowMpadded" width="10px" depth="30px" style="background: blue"></mspace></mpadded></math>
    <math><unknown><mspace id