1. Fold down follow the dashed-line to be triangle shape

2. Fold down follow the dashed-line and spread out

3. Fold the right and the left angles follow the dashed-line to abut at the bottom angle

4. Fold down follow the dashed-line and spread out for making the crinkle

5. Fold the 2 angles follow the dashed-line apart in opposite ways

6. Fold the lower-angle up follow the dashed-line

7. Fold up again follow the dashed-line

8. Fold to hide it inside the cap

9. Finish