I see that Karl Eriksen has made a false response to one of my comments. He said: That assertion is false for the example I posted. I referred specifically to two plausible mechanisms that I speculated about in 2008. I called them "skittering" and "bowling". We have had proof for some years - post my 2008 speculations - for one example of "bowling". By "bowling" I mean a "beam" (strictly a section of column) carried at the top of a toppling sheet of perimeter columns. That example is the beam that embedded in the WFC. It came from the top of one sheet of perimeter. I described it in my earlier post as "that humungous 30(?) storey piece that fell as a single sheet and - by a "bowling" action - impaled that beam into the WFC." I am conscious of this forum's "No Click" policy - the proof of where that "humongous sheet" came from and how it swiped WFC as it fell is no longer easy to access but if anyone wants it I can try to locate the evidence which is many years old. The main issue here however is that Karl's responses seem to focus on rebutting one mechanism when reality had several. And the sections of perimeter column "sheets" he is probably referring to were not displaced by either impact skittering or long range bowling.