handrails were "blasted" with ground pecan shells to create a matte surface texture. The museum has three glass-walled courtyards that bring natural light to the gallery spaces. One of them penetrates the gallery floor to bring natural light to the conservation studio on the ground floor. The landscape has been described as "Kahn's most elegant built example of landscape planning" by Philadelphia landscape architect George Patton. Approaching the main entrance past a lawn edged by pools with running water, the visitor enters a courtyard through a grove of Yaupon Holly trees. The sound of footsteps on the gravel walkway echoes from the walls on either side of the courtyard and is magnified under the curved ceiling of the entry porch. After that subtle preparation, the visitor enters the hushed museum with silvery light spread across its ceiling. Harriet Pattison played the lead role in the landscape design and is also the person who suggested that open porches flanking the entrance would create a good transition from the lawn and courtyard to the galleries inside. Pattison, who had also worked with Kahn on other projects, was an employee of Patton. She is the mother of film director Nathaniel Kahn, Louis Kahn's son who made the film "My Architect" about his father. Vaults Kahn's first design for the galleries called for angular vaults of folded concrete plates with light slots at the top. Brown liked the light slots but rejected this particular design because it had the ceilings 30 feet (9 m) high, too high for the museum he envisioned. Further research by Marshall Meyers, Kahn's project architect for the Kimbell museum, revealed that using a cycloid curve for the gallery vaults would reduce the ceiling height and provide other benefits as well. The relatively flat cycloid curve would produce elegant galleries that were wide in proportion to their height, allowing the ceiling to be lowered to 20 feet (6 m). More importantly, that curve could also be used to produce a beautiful distribution of natural light from a slot in the top of the gallery across the entire gallery ceiling. Kahn was pleased with this development because it allowed him to design the museum with galleries that resembled the ancient Roman vaults he had always admired. The thin, curved shells needed for the roof were challenging to build, however, so Kahn called in a leading authority on concrete construction, August Komendant,