As shown in the figure, in square ABCD, e and F are two points on BD, and be = DF

As shown in the figure, in square ABCD, e and F are two points on BD, and be = DF

It is proved that: ∵ quadrilateral ABCD is a square, ∵ od = ob, OA = OC, BD ⊥ AC, ∵ be = DF, ∵ de = BF, ∵ OE = of, ∵ quadrilateral aecf is a parallelogram, and ∵ quadrilateral aecf is a diamond