Dense and complex, this piece by octogenarian sculptor John Pai, now on view in a show of work by three 20th century Asian-American sculptors at Chelsea’s Tina Kim Gallery, evokes a scientific or mathematical model in flux. Piece by piece, Pai welded short steel rods together in a hands-on practice he likened to drawing. Reflecting subconscious activity and taking inspiration from music, science, architecture and more, Pai’s dynamic constructions elicit wonder at complex structures in our own thought processes and the world around us. (On view through January 29th. Note holiday hours and closures.)