<?php header('Content-type: image/svg+xml'); echo '<?xml version="1.0" encoding="utf-8" standalone="yes"?>';
function df($v){ return floor($v*100)/100; }
function lp() { echo '535.076,89.632'; }
function semicircle($r) {
	for($i = 0; $i < 1.01; $i += 0.05) {
		echo df(cos($i)*$r+400).",".df(-sin($i)*$r+300)." ";
	}
} ?>

<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" baseProfile="full"
	width="800" height="600" viewBox="100 0 800 600" xmlns:svg="http://www.w3.org/2000/svg">
	<style type="text/css"> text { font-size:40px; font-family:DejaVu Sans; font-style:italic; } </style>
	<circle cx="400" cy="300" r="250" stroke="#000000" stroke-width="2" fill="none" />
	<polyline fill="none" stroke-width="4" stroke="#FF0000" points="<?php semicircle(250);?>" />
	<polyline fill="none" stroke-width="3" stroke="#FF4400" points="541,120 <?php lp(); ?> 565,90" />
	<polyline fill="none" stroke-width="4" stroke="#004400" points="<?php semicircle(50);?>" />
	<polyline fill="none" stroke-width="2" stroke="#000000" points="650,300 400,300 <?php lp();?>" />
	<text x="450" y="270" fill="#004400">φ</text>
	<text x="650" y="180" fill="#FF0000">s = b = rφ</text>
</svg>