In "week182", back in 2002, I referred to this very nice thesis: Joris van Hoboken, Platonic solids, binary polyhedral groups, Kleinian singularities and Lie algebras of type A,D,E, Master's Thesis, University of Amsterdam, 2002, available at http://www.science.uva.nl/research/math/Onderwijs/examen/2002/scriptiejoris.ps Now I'm studying this stuff again. There are cool relations to ALE spaces and string theory, and lots more. Alas, I didn't keep a copy! It seems to be gone. James Dolan and I can't find it using Google or the "wayback" web archive. I can't locate van Hoboken, either. Does anyone have a copy, please? This is another reason people should put their theses on the arXiv! Universities should also keep electronic copies of theses in some publicly available electronic form.