This was a week for a reality check on some of the startups and older private firms that have at least a one billion dollar valuation. In recent years the tech industry has called these firms unicorns after the mythological animal resembling a horse or a kid with a single horn on its forehead. The unicorn appeared in early Mesopotamian artworks, and it also was referred to in the ancient myths of India and China according to Encyclopaedia Britannica.