Fold the square paper-cut diagonally and find out that the midpoint plane of the material is divided into three parts, one of which is folded up and the other is folded back. Flatten the material and fold it in half to draw the pattern of symmetry axis; Mark the part to be cut. Cut off the parts marked with diagonal lines. This is a round window grillage with many symmetry axes.

Fold a graph along a straight line. If the parts on both sides of the straight line can overlap each other, then the graph is called an axisymmetric graph, and this straight line is the axis of symmetry. After the positions of two symmetrical figures are fixed, there is only one axis of symmetry.