I found a paper: 'A New Method of Finding the Distribution of Prime Number', says:

We stack discs and annuluses with certain rules then turn on the light to illuminate.The projection of annuluses corresponds prime number,and the projection of discs corresponds composite number.

See; http://en.cnki.com.cn/Article_en/CJFDTOTAL-HNKX201201010.htm

Are there other physics methods for number theory?