This house sign in Graz shows a bird standing on a combination of a star and a crescent. The combination star and crescent was already known in the Hellenistic period (4th–1st centuries BCE). The crescent represents the moon, the star represents the sun or the morning star.
The crescent offers an interesting detail: it shows a face. Such a face you can sometimes see in coat of arms, as well.
Sources / More info
- Star and crescent (Wikipedia)
- travel-by-photos.com (Photo 1)