1. Cut two kinds of cardboard into a circle and sixteen pieces, as shown in the following figure:

2, a color, folded and overlapped, as shown in the figure below:

3. Fold in half again, as shown in the figure below:

4. Flip down the top edge, as shown in the following figure:

5. Open it again, fold it in half in the middle and turn it over again, as shown in the figure below:

6. Fold both sides to the middle, as shown in the figure below:

7. Fold 8 sheets in the same way, as shown in the following figure:

8. Prepare a piece of cardboard and stick the folded things on it one by one, as shown in the following figure:

9. The birthday card is made, as shown in the following figure: