Why does Venus appear to describe a pentagram in her path through the heavens?

I read that the path of Venus as seen from Earth looks like a five-pointed star or pentagram. But I don't understand why. Can someone please explain how this phenomenon comes about? And how long does Venus take to cycle through the points of its path? Is Venus the only visible celestial object whose path does... show more I read that the path of Venus as seen from Earth looks like a five-pointed star or pentagram. But I don't understand why. Can someone please explain how this phenomenon comes about? And how long does Venus take to cycle through the points of its path? Is Venus the only visible celestial object whose path does not describe a conic section?
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