Because AE=BF=CG=DH= one-third AB, BE=CF=DG=AH= trimolecular AB, EF=FG=GH=HE= 5, if the shadow area refers to the area of square ABCD after removing square EFGH, that is, the sum of the areas of four triangles, the shadow area in the figure is. If it's EHGH, it's five out of nine.