Can Single-Slit Diffraction Occur in Two Dimensions?

[slpsms6]

Considered a question regarding single-slit diffraction that has me stumped. Understand the relationship involving wavelength to width ratio and impact on diffraction pattern. But what if you made the height and width the same so that there could be two-dimensional diffraction, what impact would that have on the pattern? Thanks

 

[jcsd]

If you have circular slit you get concentric circles of maxima and minima.

 

[Integral]

Some night, open your eyes, and look though a thin curtin at a distant light source.