<?xml version="1.0"?>
<svg xmlns="http://www.w3.org/2000/svg"
xmlns:xlink="http://www.w3.org/1999/xlink" onload="init()">
<script><![CDATA[
var flag=1;
var c;
function init() {
c= document.getElementById("use")
setInterval("loop()",500);
}
function loop() {
c.setAttributeNS("http://www.w3.org/1999/xlink","href","#rec"+flag)
flag= (flag+1) % 3;
}
]]>
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<rect width="59" height="59" x="5" y="5" fill="blue" />
<text x="17" y="56" font-size="60" click="none" > A </text>
</symbol>
<symbol shape-rendering="optimizeSpeed" id="rec1" viewBox="0 0 64 64">
<rect width="59" height="59" x="5" y="5" fill="magenta" />
<text x="17" y="56" font-size="60" click="none" > B </text>
</symbol>
<use id="use" xlink:href="#rec0"/>
</svg>