Moving on, I believe it is very important to understand that on each of the 8 WTC1, 2 faces very different phenomena (and mechanics) result from whether the upper perimeter sheet or lower perimeter sheet slips to the inside during the earliest failure).
Guys, that simple fact changes everything. If the upper sheet slips (or is intentionally pushed) outwards, all behavior (and roofline measurements?) along that face changes.
We can see how this simple change in inital positioning can destroy the physical integrity of the upper block.
The lower perimeter breaks successive outer floor connections along the red line.
It strips the upper block perimeter columns from their flooring.
Pop, pop, pop, pop all the way up. (or small jolt, jolt, jolt...who knows?)
Large perimeter sheets will be seen to go into freefall from the upper block, stripped of their flooring. Sound familiar?
If the process were reversed (as shown on the left side of the building). You'd strip the lower block perimeter from it's flooring (as seen along WTC2 east face).
If this is true, what is a large part of the resistance force F which controls the building descent as measured along the WTC1 north face roofline?
Probably the perimeter-floor connections and their resistance to being destroyed?
). As soon as perimeter is shed/peeled/... there can be only floor<->floor impact, which will definitely be subject to action/reaction, and inevitable simultaneous crush down/up.