In general we do not have mathematical proof for stuff we know that we know. Neither do we always have an reference handy (not even with the help of google). Be it engineering or the access to firewood in Sweden. And getting challenged on stuff we know that we know, that are basic, does not prompt eagerness to prove it, for what proofs would be acceptable for those that does not share our knowledge? And then a "you prove it - no you prove it" is quickly started.

Therefore I am not sure this debate over Pentagon will lead anywhere. On the other hand I would be interested in a diary on what plane crashes into objects usually look like. I know formulating it would probably mean some work for you (it is that way with knowledge we normally use rather then describe) but I think it would be interesting. If you like to compare it with 911 is up to you.

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