We present a simple diffraction experiment with m -bonacci gratings as a new interesting
generalization of the Fibonacci ones. Diffraction by these non-conventional structures is proposed
as a motivational strategy to introduce students to basic research activities. The Fraunhofer
diffraction patterns are obtained with the standard equipment present in most undergraduate physics
labs and are compared with those obtained with regular periodic gratings. We show that m- bonacci
gratings produce discrete Fraunhofer patterns characterized by a set of diffraction peaks which
positions are related to the concept of a generalized golden mean. A very good agreement is obtained
between experimental and numerical results and the students? feedback is discussed.