Like this!
At least, for some particular choices of slit size, separation, and wavelength. Let me explain a little.
There may be many ways of doing this calculation, but by far the most fun is with <PERSON> path integrals. Actually, the method I used is described very well in his book QED. Essentially, interference is caused by the different lengths of the paths, since a photon traveling a different distance is in a different phase of it's cycle. So, by picking a set of paths for each location on the final screen, I just calculated the phase associated with each path, added them together, and took the absolute value to get the amplitude. Technically, I did:
$$\big|\sum_i \exp(i d_i k)\big |^2,$$ where $d_i$ is the distance of each path and $k$ is the wavenumber.
The arrangement of the slits is as follows:
I have also drawn 4 representative paths, as an illustration. 795
Each point on the screen used 24 paths, as each slit was simply broken down into 2 points, it's edges.
For the actual dimensions, I used arbitrary units, but eventually made choices which roughly correspond to the diffraction of red light. Choosing the wavelength to be 7, the half-slit sizes were each 3500, the center-to-center distances of the slits were all 10000, and the distances between the screens were all 10000000. For the three plots above, I varied the wavelength from 7 (on the left) to 12 to 20 (on the right).
All this is in a spreadsheet, where you can change the various distances to some degree (although you can't improve the resolution, that would require quite a bit more work). You can check out the spreadsheet here. The apparent asymmetry is certainly due to the lack of resolution.
Again, I'm not sure this gives you the answer you want, because everyone who says "it depends on the distances involved" are all correct. But, at least this gives you a flavor of what such a pattern might look like.
As an editorial note: this was super fun, but I'm sure not it was the easiest way to do this calculation! 441