It was created in three phases, the platform and building itself, then the precast “shells,” and finally the exterior. The “shells” were the hardest thing to create. Three to four different ideas were pondered over during 1957-1961. Then in 1963 Utzon’s four year old son gave him the idea that every piece of “shell” should be built as if it where taken from the same sphere. He showed everyone this idea by using orange peels.