Paper and pen

operational approach

1. Prepare a square piece of paper and a pen.

2. Fold one corner of the square paper in half to get two diagonal lines in the middle.

3. Fold up the corner below the square.

4. Hold the midpoint of the bottom edge with both hands and squeeze into the triangle below.

5. Fold the right corner to the left by one third.

6. Fold the left corner by one third to the right.

7. Turn the paper over, it looks a bit like a swallowtail fish.

8. Draw an arc on the left corner with a pen, separate the head, draw an eye on the head, and then draw a few short lines from the four corners on the right with a pen to expose the fins, and the swallow will be folded.