<p>Is it OK to send in another essay? I feel that my additional essay could paint a more complete picture of myself, but would the adcom be really crossed because I think they stated their "no additional stuff" policy somewhere in the instructions?</p>
<p>Absolutely not. What's wrong with Columbia's essay? Is there some limiting factor that prevents you from providing an accurate picture of yourself? Think of this from an adcoms perspective: They have 20 minutes(give or take) to read your application. Do they want to sift through another 2(or more) pages of an essay if they don't have to? No way in hell. Focus on making the single essay as dense in details about yourself as possible, and the Why Columbia questions to further elaborate. There should be no need for an essay. The only things I would say are worth submitting are:
1. Recommendations if you know someone really well who is not a teacher.
2. Supplemental arts/music material if you are passionate about either.
3. A scientific research paper abstract if you're interested in science.</p>