Vivi continues her explanation, visualizing the four types of islands - Summer, Spring, Fall, and Winter - each with their own four seasons. "In short, in order to survive sailing across Grand Line, you should be able to endure all 16 types of seasons, from the summer of Summer Island all the way to the winter of Winter Island." Usopp, still hammering, replies, "Of course, there still are exceptions and unknown climates." He realizes, "I see... so the reason why Grand Line has such unpredictable climate, is due to being trapped between all these islands, each with their own distinct climate..." Sanji, looking through binoculars, confirms, "Exactly." The Going Merry sails on as Vivi concludes, "That's why climate stabilization signals the presence of an island nearby...!" Sanji spots something ahead. "You're right... I can see land up ahead!"