"Diffraction Grating" We did a diffraction experiment involving single slits, double slits, and a diffraction grating. Apparently the diffraction grating that we got was "different" (according to a classmate). The diffraction grating was "criss-crossed" and didn't produce any dark fringes on the interference pattern. Can anyone tell me what one of these criss-crossed gratings is called so that I can figure out (i.e. Google) what the diffraction pattern would look like? Thank you!