Apple has scored a patent for the large round glass structure that leads customers down to its retail store in Shanghai. Awarded Tuesday by the US Patent and Trademark office, the patent known as “Glass building panel and building made therefrom” describes the unique design of the cylinder.

The structure is made of huge glass panels united by metal joints. But to achieve the cylindrical design, the glass panels had to be manipulated to curve precisely into the right shape. The structure itself also had to be strong enough to support itself and the stream of customers going back and forth. As such, the cylinder was outfitted with glass beams extending from the inner cylinder to the outer edges. Glass fins connect each area where adjacent panels meet.