Located along a row of utilitarian high-rise buildings on a busy thoroughfare in Chicago's Streeterville neighborhood, one 23-story tower just east of Michigan Avenue stands out: its facade is a lively mix of color, light, and form. Curved glass encloses a ground-level lobby; a sky garden on an upper floor projects beyond the precast-concrete grid that composes the building's facade. Visually, it looks like a set of giant building blocks, piled high by a child'and with good reason.