I too would like to know the significance of the flagpole and the fish tank. "There are, of course, the classic general danger signs such as a fish-tank in the foyer, and a flagpole outside. Either, evidently, is a classic sign of a company in its terminal stages." Evident to whom? Are you being serious or facetious?

My guesses: If a company has a flagpole, then I would check the flag. In good condition: good sign. In bad condition: probably a bad sign. Bare pole during working hours (especially if it has a light aimed at the top): probably a bad sign. A fish tank without fish in plain sight is probably a bad sign unless someone is cleaning it. An active fish tank contributes to the ambiance, so I would wonder what purpose it serves. And at any rate, a live fish tank means that company resources are being used on things that are not absolutely essential to the business.