Kuplen is a fully embedded digital musical instrument, whose tactile, tiltable surface is mapped to parameters of a physical modelling synthesis sound engine. The underlying stiff string physical model, excited by a bow with movable damping element, can produce a variety of pitches and timbral qualities. Players reported their interest in exploring the expressive capabilities of the instrument. Indeed, by combining free-form modes of interaction with established higher-level descriptor mapping strategies, Kuplen invites the user into novel sonic explorations and gestural controls over an exploratory framework of the physical model.