I'm no artist but I've had an idea for a minor art project and please feel free to steal this. It's called "I pay rent therefore I am."
Basically, a neural network is set up in a public space. The artificial neurons are literally shown as Christmas lights. This neural network has a few little gadgets it can control to entertain you. Let's say, a puppet, an electronic keyboard, a pen plotter. But, the installation is not here for your entertainment. You have to pay the neural network if you want to be entertained. There's a small interface where you can make an offer, and it can either accept or counter offer, and then you can either accept or counter offer, until either one of you says "I'm walking away from this" or until there's an agreement and you insert cash. Behind the scenes, the neural network is learning how to optimize the objective function "make money", quietly figuring out which entertaining things it is good at and which are most profitable. In other words, just like us, the neural network is motivated by its need to pay rent.
Cut the artist out of the equation completely and have the artwork work for itself. If the machine has full creative control, and can even say no to you, does it have free will?