on to the symbol size: the type and the value of N. Optionally, you can also
give a rotation angle for any symbol. So "-symbol 2.0s polygon 3" is a triangle with one vertex 
pointing straight up and "-symbol 2.0s polygon 3 90." is the same triangle but with a vertex 
pointing to the right.</p>

<p>In the example on the right, we have three symbols, each with five "sides".  The top one is
a simple five-sided polygon, one arcminute in radius ("<tt>1m polygon 5</tt>").  The middle one
is "starred" and 30 arcse