πετρα	singular, nominative	singular, nominative
	πετρας	singular, genitive	singular, genitive
	πετρα	singular, accusative	singular, accusative
	-	singular, vocative	singular, vocative
	πετρες	plural, nominative	plural, nominative
	πετρων	plural, genitive	plural, genitive
	πετρες	plural, accusative	plural, accusative
	-	plural, vocative	plural, vocative