<feature_model name="Cellphone">
<feature_tree>
:r cellphone
	:o wireless
		:g [1,*]
			: infrared
			: bluetooth (bluetooth)
	:m accu_cell
		:g [1,1]
			: li_ion (li_ion)
			: ni_mh
			: ni_ca (ni_ca)
	:m display
		:g [1,1]
			: color (color)
			: monochrome
</feature_tree>
<constraints>
c1: ~bluetooth or li_ion
c2: ~color or ~ni_ca
</constraints>
</feature_model>
