the three things you need

On Twitter people were posting the three things they need to write. It was interesting because people were taking it in all sorts of different ways--very abstract or big-picture, or very particular and concrete. Some were external things and some were internal. So for instance, Virginia Molhere listed "A decent pen (non-traditional ink color helpful)" as one of her three, and Aliette de Bodard listed "A universe (basic idea of the thought system and where my MC is on the scale)."

Care to share your three? Not limited to writing--apply it to the creative endeavor of your choice.