For graphics output, this will typically be a plotting command, such as "Plot[x,{x,0,1}]". For typeset output (i.e., the PictureType property is set to "StandardForm" or "TraditionalForm"), any expression can be given; its result will be typeset and displayed. Note that it is the result of the expression that is displayed, so do not make the mistake of ending the expression with a semicolon, as this will make the expression evaluate to Null.

You might find it more convenient to define the command in Mathematica as a function and then specify only the function call as the MathCommand. For example, when using this class from a Mathematica program, you might do this: