In trapezoidal GDBE, S△GDB=S△EDB (the same height as the bottom).

∴S△GDB-S△BDM=S△EDB-S△BDM，

∴S△DGE=S△GEB，

Similarly, s △ gke = s △ gfe.

∴S shadow =S△DGE+S△GKE

= S△GEB+S△ Global Environment Facility,

=S squared GBEF,

=4×4

= 16