Miscellany

<Machine><define name="sphere"><Sphere args="0,0,0,1"/></define><define name="cylinder"><CylinderZ args="0,1,2,1"/></define><define name="inner">    <HalTranslate var="y" x="0" y="1" z="0">	<use name="sphere"/>	<HalTranslate var="z" x="0" y="0" z="1">	    <use name="cylinder"/>	</HalTranslate>    </HalTranslate></define><use name="sphere"/><HalTranslate var="x" x="1" y="0" z="0">    <use name="sphere"/>    <use name="inner"/></HalTranslate></Machine>