Not Orignial Research, there exists a huge literature. Mmx, there were 3 symmetrical collapses on 9/11, not one. And of course there have been many dozens, if not hundreds of symmetrical building collapses outside 9/11, all of them due to controlled demolition.  There are zero examples of symmetrical collapse from fires, impact damage, or anything besides contolled demolition.  Achieving symmetry in a building collapse requires that all of the vertical supports fail at the same time, or a least fail in an evenly spaced, symmetrical manner. The odds of this happening by chance are very small, especially considering the impact damage and fires were asymmetrical. For it to happen three times in one day is profoundly significant, statistically speaking.