Several problems of two-dimensional propagation and scattering of ultrasonic waves are simulated and visualized by using a program based on the mass-spring lattice model. The problems are related to reflection, refraction, and diffraction of ultrasonic waves. It is found that all numerical results are in good qualitative agreement with the wave mechanics. Features incorporated into the updated program are explained. Though the present state is far from our ultimate goal to develop a complete simulator of ultrasonic testing, the developed software is useful for educational purposes even at the present stage of development. ©2001 American Institute of Physics.