'''Defining'''
<pretexcode>
\defineoverlay[reference name][commands]
</pretexcode>
Better put your commands in braces.
You can use defined overlays everywhere, where there's a <tt>background</tt> option.
<pretexcode>
\defineoverlay[tea][{\green\ss\bf GREEN TEA}]
\framed[height=40pt, background=tea, align=middle]%
{\em today\\for sale}
</pretexcode>
You can use this also with pictures. See also [[Logos]].