1  <?xml version="1.0" standalone="no"?>
 2  <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG April 1999//EN" 
 3    "http://www.w3.org/Graphics/SVG/svg-19990412.dtd">
 4  <svg width="4in" height="3in">
 5    <defs>
 6      <symbol id="Triangle" min-x="0" min-y="0" max-x="100" 
 7        max-y="100" ref-x="0" ref-y="50">
 8        <path d="M 0 0 L 0 100 L 100 50 z"/>
 9       </symbol>
10     </defs>
11    <desc>An double-headed arrow example using markers
12    </desc>
13    <path d="M0 0">
14      <!-- Place an arrowhead rotated 180 degrees at the 
15           beginning of the path -->
16      <marker href="#Triangle" width="200" height="200" 
17            style="text-transform: rotate(180)"/>
18      <data d="M 2000 2000"/>
19  
20      <!-- Turn off markers in the middle of the path -->
21      <marker href=""/>
22      <data d="L 4000 2000 L 4000 4000"/>
23  
24      <!-- Place an arrowhead at the end of the path-->
25      <marker href="#Triangle" width="200" height="200"/>
26      <data d="L 6000 4000"/>
27    </path>
28  </svg>