This affordable 2D diffraction grating slide can be used with a laser to demonstrate the diffraction of light. It has three different areas: 100, 300, and 600 lines per inch. Just shine the laser light through one of these areas on the slide and watch the projected 2D diffraction pattern on the screen or wall behind it. Use it to calculate the exact wavelength of the laser light by measuring the distance between the slide and projection screen, and the distance between diffraction patterns.
