2.3 We generally assume that the gap size in the slits of a diffraction grating are negligibly small. But if we remove this assumption and consider a diffraction grating with finite-sized gaps, we see a single-slit pattern superimposed upon the usual regularly-spaced bright fringes from the grating. An example of such a case is shown in the diagram. If not for the single-slit effect, all these fringes would be equally-bright. \\