Mapping exercise

Here, the initial "blobby" objects in the screenshot of WTC 7's collapse video (on the right) are mapped to the damage shown in a pre-collapse picture (on the left). The red and green lines show the corresponding areas between the pictures.

It seems that the blobs have received unwarranted attention. It is more fruitful to demand explanations for the sudden, symmetrical onset of the destruction (meaning that all the 80 or so support columns had to give in at the same instant) and the almost vertical progression of the "collapse" to the ground at nearly freefall speed (meaning that the roof came to the ground as if resisted by mere air).