The client called me, asking for an illustration. I agreed and he gave me the following brief: "I want an image of a stylised new moon - an illustrated perfect circle - black, with a black drop-shadow with a blending mode of 'Multiply' on a black background. I obliged, and sent him an image of what appeared to be a consistently black square. "Nope" he said, "I can still make out the outline of the new moon and a touch of the drop shadow". "Aha!" I cried triumphantly. "I never made the moon or drop-shadow. What I am giving you is in fact, a consistently black square without a pixel of detail or variation". "Sure" he replied, unfazed by my jubilation and edge of superiority. "But I can still imagine it there, which is altering my ability to see a consistently black square which is ultimately what I'm after". "So essentially you want me to create an image of a stylised new moon - an illustrated perfect circle - black, with a black drop-shadow with a blending mode of 'Multiply' on a black background that also stops you from thinking of or seeing in your mind an an image of a stylised new moon - an illustrated perfect circle - black, with a black drop-shadow with a blending mode of 'Multiply' on a black background that is essentially a consistently black square".
"Exactly. And I want it to be 800 pixels square".