iable name like
`<font color="#82140F"><code>latitude</code></font>', since it is not a keyword, but Gri is not, since it
might like to use that word itself in a new command.)
<p>
You should not use names beginning and ending with double periods,
because Gri uses names like that to store built-in variables for its own
use (e.g., `<font color="#82140F"><code>..xsize..</code></font>' saves the width of the plot).
<p>
To store a number into a variable, use a command like
<p>
<TABLE SUMMARY="Example" BORDER="0"