A “user interface” is simply one type of dynamic picture. I spent a few years hanging around various UI design groups at Apple, and I met brilliant designers, and these brilliant designers could not make real things. They could only suggest. They would draw mockups in Photoshop, maybe animate them in Keynote, maybe add simple interactivity in Director or Quartz Composer. But the designers could not produce anything that they could ship as-is. Instead, they were dependent on engineers to translate their ideas into lines of text. Even at Apple, a designer aristocracy like no other, there was always a subtle undercurrent of helplessness, and the timidity and hesitation that come from not being self-reliant. It’s fashionable to rationalize this helplessness with talk of "complementary skillsets" and other such bullshit. But the truth is: An author can write a book. A musician can compose a song, an animator can compose a short, a painter can compose a painting. But most dynamic artists cannot realize their own creations, and this breaks my heart.