The architecture of the Space Needle is the result of a compromise between the designs of two men, Edward E. Carlson and John Graham, Jr. The two leading ideas for the World Fair involved businessman Edward E. Carlson's sketch of a giant balloon tethered to the ground (the gently sloping base) and architect John Graham's concept of a flying saucer (the halo that houses the restaurant and observation deck). Victor Steinbrueck introduced the hourglass profile of the tower. The Space Needle was built to withstand wind speeds of , double the requirements in the building code of 1962. The 6.8 Nisqually earthquake jolted the Needle enough in 2001 for water to slosh out of the toilets in the restrooms. The Space Needle will not sustain serious structural damage during earthquakes of magnitudes below 9.1. Also made to withstand Category 5 hurricane-force winds, the Space Needle sways only per of wind speed.