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>
29