Diffraction can occur with tilted light arrays, not just with normal incident lights, as all light diffracts when its path is restricted. The normal incidence case is often emphasized in teaching due to its simpler mathematical treatment. The discussion raises questions about the specific context of diffraction, including the type of light and the nature of the diffraction grating involved. There is some confusion regarding terminology, particularly the use of "tilted light arrays" versus "diffraction gratings." Overall, the conversation highlights the complexities of diffraction phenomena beyond the standard introductory examples.