Yutaka Nishiyama

Yutaka Nishiyama (西山 豊, Nishiyama Yutaka, born 21 October 1948) is a Japanese mathematician and professor at the Osaka University of Economics, where he teaches mathematics and information.

He is known as the "boomerang professor".

[1] He has written nine books about the mathematics in daily life.

[2] The most recent one, The mystery of five in nature, investigates, amongst other things, why many flowers have five petals.