“Smaller Worlds” zeroes in on the diorama—that three-dimensional world contained in a box, behind glass, and most often seen at science fairs and museums of natural history. Ludwig Múzeum Budapest, however, frames the diorama within the genre of fine art. Artists from the U.S., England, the Netherlands, Poland, Germany, Slovakia, and Trinidad come together to reveal the form’s full artistic potential. —Clara Molot