So far I've provided very little content, mostly annonymous spelling corrections.
Planed write-ups
Write a page on Warnock's Algorthym (?), the recursive subdivision method for rendering.
0. If there are no objects in the viewport, stop. 1. If only one object in viewport, render it. 2. If the closest object covers the entire viewport, and all other objects are completly behind it, render the closest object. 3. Otherwise, cut the viewport into 4 parts and recurse for each.
This reduces each 'part' of the image to a case that is simple to render. Nb. for case 2, the closest points on all the other objects must be further away from the camera than the furthest point on the covering object.