The number 4 seems to hold some significance in "Lunacy". The gateway to the City of Moons can only be accessed once every four years. Correspondingly, the wind blows only once every four years in Misty Town. In the City of Moons, the object is to free four butterflies, each of which connects roughly to one of the four elements: earth, water, wind and fire (light). When Fred descends into the well to find the gateway to the City of Moons it is these four elements that open the portal when brought together.