The obelisk symbolized the sky deity Ra and during the brief religious reformation of Akhenaten was said to be a petrified ray of the Aten, the sun disk. It is hypothesized by New York University Egyptologist Patricia Blackwell Gary and "Astronomy" senior editor Richard Talcott that the shapes of the ancient Egyptian pyramid and obelisk were derived from natural phenomena associated with the sun (the sun-god Ra being the Egyptians' greatest deity). It was also thought that the deity existed within the structure. The Egyptians also used pillars extensively.