Of all human features sex is the only one, which, as a matter of fact, is not vice, because it is peculiar to all living beings. Everything may be elevated to the level of art and brought down to filthy triteness. But without this no matter faulty or blameless infinite story one can't do. People managed both to ennoble it and to bring down to filthy profanity. Such is human nature. We may see some sense and turn everything into nonsense. These two creatures are a visual symbol of eternity of sexual relations. And the parrot represents a philosophically-contemptuous attitude to life. The yard-keeper, on the contrary, is an indifferently dull creature. But a voluptuous couple soaring in the skies is indifferent to anything, except love.