Freakaloin wrote:symetrical fall of a burning building is impossible...
I'll qualify this before agreeing to it.
A burning building falling symmetrically into its footprint is conceivable -- if the fire is located in the center of the building, and subsequently weakens the support structure in the center, so that all walls are pulled inward onto each other.
You tell me - if a massive chunk of debris smashes through one side of a building, and that side is burning so hot that it actually weakens steel support beams on that side of the building, how is it that all other support beams around the circumference and center of the building allow the structure above them to collapse as easily as the area where the beams are physically weakened?
You can take an object as tall and as heavy as you would like to, with as much support as you would like to. If you weaken any part of the support structure on a single side - or even two sides - the collapse is going to occur in the direction of that weakened support. It is a fundamental principle of physics that all energy follows the path of least resistance, and that applies here as well. This doesn't change just because the building is really, really big.
If there is a 20-story hole in the side of a building, how is it conceivable that all 4 sides would fall at the same speed?