Hellman's Mathematical Playground
This section is under construction and will have links to papers and lectures that try to make stimulating mathematical results accessible to motivated students at a much earlier level than normal. Unless otherwise specified, typical (not AP) high school level math is all that is required. However, motivation and perseverance are required to leverage that background in order to understand math that usually is not seen until higher level university courses.
I have called this a Mathematical Playground to try and remove the serious feeling that usually pervades such material and scares off too many people. My wife has often said that students would find algebra much less intimidating if we called it number puzzles instead.
With that preamble, here are the currently available link(s):
Spheres in high dimensions
This page (combined with the first page on hyperspheres) can be viewed in Romanian courtesy of azoft.