With its trio of inward-sloping tiers, the Smithsonian National Museum of African American History and Culture (NMAAHC) cuts a striking profile on the National Mall. Yet look closer at the 409,000-square-foot building, designed by Freelon Adjaye Bond/SmithGroup, and you’ll discover that the seemingly monolithic tiers—which the team refers to as a corona—are actually composed of thousands of custom-designed filigreed panels.