Among the many brilliant and confounding works in David Hammons’s current retrospective is one entitled A Movable Object/A Japanese Garden (2012). The piece centers around a wheeled flatbed dolly, a perfectly banal machine bearing strange cargo: chunks of broken asphalt interspersed with unrecognizable articles of clothing and lengths of colorful tulle. Facing this apparent enigma, the mind grasps after established meanings. It registers familiar qualities like texture, color, and density. It tries to establish contrasts between the jagged opacity of the asphalt and the smooth translucency of the fabric. It asks questions: what is being said here about color, about blackness, about materiality or meaning? Searching for cues, the viewer’s eye finds a warning sticker on the dolly’s side: DO NOT RIDE OR OVERLOAD. In an elliptical manner that is typical of Hammons, this caption reads as a wry, sardonic joke. Of course the “movable object” can’t be ridden, it’s an artwork. And not only is the dolly loaded with hundreds of pounds of asphalt; the sculpture seems to be overloaded with potential meanings, not all of which resolve or align. There’s a gnomic levity to this humor but also an air of faintly hostile warning: the joke’s on the person …