Playing musical instruments involves producing gradually more challenging body movements and transitions, where the kinematic constraints of the body play a crucial role in structuring the resulting music. We seek to make a bridge between currently accessible motor patterns, and musical possibilities beyond those - afforded through the use of a robotic augmentation. Guitar Machine is a robotic device that presses on guitar strings and assists a musician by fretting alongside her on the same guitar. This paper discusses the design of the system, strategies for using the system to create novel musical patterns, and a user study that looks at the effects of the temporary acquisition of enhanced physical ability. Our results indicate that the proposed human-robot interaction would equip users to explore new musical avenues on the guitar, as well as provide an enhanced understanding of the task at hand on the basis of the robotically acquired ability.