<?php header('Content-type: image/svg+xml'); echo '<?xml version="1.0" encoding="utf-8" standalone="yes"?>'; 
function l($n, $m, $r=1) {
	for ($x = 1-$r; $x < 6; $x += 1) {
		echo '<line '.$n.'1="'.($x*100*$r-($r-1)*300).'" '.$n.'2="'.($x*100*$r-($r-1)*300).'" '.$m.'1="0" '.$m.'2="600" stroke-width="1" stroke="#A0A0A0" />'."\n";
	}
}
?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
<svg xmlns="http://www.w3.org/2000/svg" version="1.1" baseProfile="full"
	width="500" height="400" viewBox="0 0 500 400" xmlns:svg="http://www.w3.org/2000/svg">
	<style type="text/css"> text { font-size:14px; font-family:DejaVu Sans; } </style>
	<?php
	l('x', 'y');
	l('y', 'x', -1);
	?>
	<line x1="0" y1="300" x2="600" y2="300" stroke-width="1" stroke="#000000"/>
	<text x="195" y="320">2</text>
	<text x="395" y="320">4</text>
	<polyline fill="none" stroke-width="1" stroke="#C04422" points="<?php
	for ($x = 0.6; $x < 3.7; $x += 0.07) {
		echo floor($x*100).",".floor(300-($x-1)*($x-2)*($x-3)*100)." ";
	}
	?>" />
	<rect x="90" y="150" width="15" height="10" stroke="#000000" fill="#C04422" stroke-width="3" />
	<text x="110" y="160">Equation 1: y = (x-1)(x-2)(x-3)</text>
</svg>