Chicago — Mixed macroeconomic signals lurked behind many of the charts displayed at the Home Improvement Research Institute’s (HIRI’s) Industry Summit last month. But presenter J. Walker Smith stressed that the fault lies in ourselves, not the economy. He pointed to several companies outside the home improvement industry that have shown amazing growth — Apple, Hyundai and Zappos, for instance. “These companies have shown unprecedented success during the third-worst downturn in U.S.