He was the master of the tall order. Bruce Graham, who died March 6 at 84, designed two of the biggest, most famous and most starkly beautiful buildings in the world, both for Chicago, where he spent almost his entire career at Skidmore, Owings & Merrill. In 1970 the 100-story John Hancock Center was a revolution in skyscraper design. Working with Skidmore's brilliant engineer Fazlur Khan, Graham conceived a tapering tower with an exterior system of structural supports, including massive X-braces that made its façade a knockout emblem of architectural force. In 1974 Graham and Khan produced another masterpiece with the Sears Tower (now the Willis Tower). Once the world's tallest building, it drew the severe black box of Mies van der Rohe into the setback forms of older skyscrapers like the Empire State Building. Graham's personal philosophy was as direct as his architecture. Buildings, he once said, should be "clear, free of fashion and simple statements of the truth."