For me 'the Prisoner' is wheels within wheels, circles within circles, and at one point the Prisoner even tries 'squaring the circle!' the ending is the beginning, and that makes it a viscious circle. In 'Many Happy Returns,' the Prisoner escapes, and is brought back to the point where he started from, completing the circle in fact. It is no wonder the Prisoner tells the maid that he's new here, he only arrived the other day during the previous episode!
It can also be said that 'the Prisoner' is a cycle of events which begins with the Prisoner resigning his job, caused by the events of 'Fall Out.' After all 'Fall Out' has nothing to do with 'fallout' as in nuclear fallout. But a falling out amongst themselves, as witnessed during 'Fall Out.'