This image alone contains both MER perimeter corners, which is over half of the entire 75-77 fl MER west perimeter.
It also contains 2 large curved perimeter sheets (bases marked in
yellow and pink) with a line of bent and ripped columns along their
lower edges. One sheet is over 9 stories tall and 7 panels wide, which
is over 1/3rd of the whole width of the building.
Note there are 2 distinct types of sheets:
1) Rectangular and rigid: MER perimeter sheets
2) Bendable, curved sheets: More flexible standard perimeter sections
bolted together as seen sheets marked wioth yellow and pink.
Reconstructed model of the west wall failure line
The 4 large pieces fit within the original wall as shown.
Rip along top of MER panels
NW corner 78th fl spandrel rip
SW corner 78th fl spandrel rip
Reconstruction of wall above floor 78
Slow motion video of the beginning of collapse from the south shows how a
mass of perimeter wall just above the MER 75-77th floor region
protrudes westward and goes into free-fall.
High res of image here
