This artist uses a Mindstorms robot to create paintings on canvas. (The article isn't clear on what version of Mindstorms he uses).
The top photo is a picture of himself with his rig. The middle photo is a painting of his wife created by the robot. The bottom photo is the actual painting apparatus: a wheel of colored, wax sticks that "paint" on a heated canvas. The artist programs the robot to paint the dots in particular locations, as the apparatus moves in rows up and down the painting. The article about his work is
Could this be done with an NXT???