Just a vaguely related anecdote, I consulted for a company that had two offices on a river, in old converted houses, separated by a marina. Running a cable prov

Just a vaguely related anecdote, I consulted for a company that had two offices on a river, in old converted houses, separated by a marina. Running a cable proved problematic for various reasons, both bureaucratic and relating to the nature of the site. To connect the networks between the two buildings, they had a laser connection set up in the widow's walk on the buildings. It worked great except when it was foggy or raining very heavily, or when the marina moved a sailboat so that its mast blocked the beam.