2. Divide the bottom of the triangle into five equal parts with a flat angle of 180 degrees, each part is 36 degrees.

3. Fold the right corner of the triangle to the left to make it coincide with the corresponding sides in four positions.

4. Fold the newly folded triangle in half again along the center line.

5. Fold back the remaining fifth in the upper left corner and align with the rightmost line. This is the ten-fold method, also known as the pentagonal method. There is no protractor at hand. Fold the left and right corners in half along the center of the bottom edge, and constantly adjust the angles until the two outer edges are aligned with each other's creases.

6. The fully folded shape is shown in the figure below.

7. After folding, draw five patterns of window grilles, one with three strokes, namely a big arc and a big crescent, and add a stroke to the center of the bottom to draw the center of the circle.

8. Cut along the drawn pattern

9. Unfold the cut colored paper, and a beautiful five-petal flower will be displayed in front of you.