Just for fun, let's make the pressed button have more bling:

Code
	<element name="pushbutton_rect" defstate="0">
		<rect state="0">
			<color red="0.0" green="0.0" blue="0.0" />
		</rect>
		<rect state="0">
			<bounds x="0.02" y="0.02" width=".96" height="0.96" />
			<color red="0.92" green="0.91" blue="0.75" />
		</rect>
		<rect state="1">
			<color red="0.5" green="0.5" blue="0.5" />
		</rect>
		<rect state="1">
			<bounds x="0.02" y="0.02" width=".96" height="0.96" />
			<color red="0.0" green="0" blue="0" />
		</rect>
		<disk state="1">
			<bounds xc=".5" yc=".5" width=".90" height=".90" />
			<color red="1.0" green="1.0" blue="0" alpha = "0.50" />
		</disk>
		<disk state="1">
			<bounds xc=".5" yc=".5" width=".50" height=".50" />
			<color red="1.0" green="1.0" blue="0" alpha = "0.85" />
		</disk>
		<text string="Pressed" state="1">
			<color red="1.0" green="0.0" blue=".25" alpha = "1.0"/>
			<bounds xc=".5" yc=".5" width="1.0" height="1.0" />
		</text>
	</element>
[Linked Image from i.imgur.com]