PITTSBURGH, Pennsylvania (AP) -- One is a sprawling house exemplifying Frank Lloyd Wright's early Prairie style. The other is a skyscraper, a rare vertical work that was one of the architect's last projects before he died in 1959.The century-old Darwin D. Martin House in Buffalo, New York, and the H.C. Price Company Office Tower and Apartments, built nearly five decades ago in Bartlesville, Oklahoma, have undergone restoration and will soon be flanked by new museums and visitor centers designed by two architects currently in vogue -- Toshiko Mori and Zaha Hadid.The unrelated projects are the focus of an exhibition through January 15 at the Carnegie Museum of Art in Pittsburgh, about 70 miles northwest of another building designed by Wright and considered to be his greatest architectural feat: Fallingwater.On display are Wright's original pencil sketches and meticulous ink drawings that show the evolution of the two buildings from conception to construction, while typed letters to clients reflect his almost fanatical concern with detail -- and routine requests for money.The exhibition also features angular office chairs and window frames that resemble tree branches -- finishing touches that Wright carefully added to complement the structures.The buildings mark two important periods in Wright's lengthy career, said Raymund Ryan, curator of the museum's Heinz Architectural Center. Nearly five decades elapsed between the projects, but both demonstrate Wright's so-called organic style, which blended structural forms with their natural surroundings and followed strict geometrical patterns."The central theme throughout his work is a synergy between the organic and the geometric," said Ryan, who added that Wright's buildings emphasize openness and strong connections between interior and exterior spaces."It's this notion of being inspired by nature," he said.Photographs and drawings of the Martin House, commissioned in 1902 by a Buffalo soap company executive who was Wright's longtime patron and friend, show an elaborate complex of buildings skirted by a covered walkway and gardens. It fell into disrepair after the Martin family lost its fortune during the Depression in the late 1920s, but has been undergoing a multimillion-dollar restoration in recent years.The restorers held a design competition for a new visitors' center, bookstore and cafe to be built at the site. They selected a proposal by Toshiko Mori, a Japanese-born architect who is also the dean of Harvard University's Graduate School of Design. The Carnegie exhibition has a scale model of the planned structure, which has a concave roof and floor-to-ceiling windows facing the Martin House.One thousand miles from Buffalo, in Oklahoma, plans are under way to build a museum dedicated to Wright's Price Tower, designed by the Iraqi-born architect Zaha Hadid. Computer screens at the Pittsburgh exhibition show three-dimensional views of the low, sloping building with transparent, colored roof panels through which visitors will be able to see the tower.The London-based Hadid, who won the 2004 Pritzker Prize, has said her Arts Center is meant to "flirt" with the 19-story skyscraper, which was originally conceived as an office and apartment space but was redesigned in 2001 as a boutique hotel. Wright described the high-rise as "the tree that escaped the crowded forest" as its floors radiate from central load-bearing shafts, like branches from a tree trunk.The new buildings by Mori and Hadid are set for construction in the next few years, according to the Carnegie curator Ryan."All of the designs are complementary to Wright's, but in no way mimic them," he said.Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.