<defs>
   <polygon id="meinU" points="0 0, 50 0, 50 150, 150 150, 150 0, 200 0, 200 200, 0 200"/>
</defs>

<use xlink:href="#meinU" x="10" y="10" fill="green" stroke="red" stroke-width="3"/>
<use xlink:href="#meinU" x="310" y="110" fill="blue" stroke="yellow" stroke-width="3"/>