1, prepare a piece of red square paper.

2. Fold the paper in half, fold the fold line inward once, and smooth the crease.

3. Starting from the lower left corner, cut the shape of a "mouth" upwards, and then cut it to the right around the outline of the word "mouth" until it reaches the lower right corner.

4. Then, unfold the cut red paper, and fold up the lower part of the happy character to make it coincide with the upper part.