A random thought occurred to me this morning: If someone asked me how often Venus reaches a favorable elongation, my first response would be "About every other year". After all, Venus's synodic period is 584 days--though this is less than two years, the odds seem to favor any given apparition skipping a year.Yet, it also occurred to me that Venus returns to the same spot in the sky every eight years, which means that given any two randomly-chosen apparitions, Venus has a one-in-eight chance of reaching elongation/conjunction/ etc. in two consecutive years.Does this sound right, folks?