Spacing between numbers should gradually increase (from minimal spacing between 0 and 1 to largest between 5 and 6).
<math xmlns="http://www.w3.org/1998/Math/MathML" display="block"> <menclose notation="box"> <mn>0</mn> </menclose> <menclose notation="box"> <mn>1</mn> </menclose> <mspace width="verythinmathspace"/> <menclose notation="box"> <mn>2</mn> </menclose> <mspace width="thinmathspace"/> <menclose notation="box"> <mn>3</mn> </menclose> <mspace width="mediummathspace"/> <menclose notation="box"> <mn>4</mn> </menclose> <mspace width="thickmathspace"/> <menclose notation="box"> <mn>5</mn> </menclose> <mspace width="verythickmathspace"/> <menclose notation="box"> <mn>6</mn> </menclose> </math>