What's the reason double-slit experiment can't be explained by edge effects rather than quantum interference? Say we had exactly this...

But instead, it was a PING PONG GUN (imagine as table tennis players use to train),
throwing out PING PONG BALLS.  The two slits are say 20 cm wide, and the observing screen is say 5m distant.
If the ball goes through the EXACT MIDDLE of a 20cm slit, it will travel in a perfectly straight line and make a "dot" on the observing screen.
If the ball travels nearer and nearer to the left or right edge of a slit, the flight path will bend slightly towards that side. For example, due to electrostatic force (rather like how a vertical pour of water from a faucet will bend slightly as your hand approaches).
Note that this is not some sort of fantasy; you could very easily organise for the ball path to bend slightly when near an edge, using either electrostatic force, magnetic force, aerodynamic factors or other forces, with the correct material of balls and slits (substitute small metal balls and slits of magnetic material .. whatever).
Indeed, you could trivial arrange so that precisely this famous image

is the outcome.
This is the "trivial mechanical bending" explanation of "all this interference pattern stuff".
Can you help me understand in a clear way, What is the explanation of why this is not at all the explanation?
 A: Nope. The important thing about the double slit experiment isn't that you find a wavy pattern on the screen, it's that the output on the screen is not equal to the output you get with only one slit open, plus the output you get with only the other slit open. The particular pattern that one slit makes by itself doesn't matter.
A: We can't explain it like you want, because try closing one of the slits first. Then do the experiment. Then do the same for the other and do the experiment. Classically, you'd expect, that both slits will function independently, hence you won't receive an interference pattern but instead a summation of intensities from each slit individually. But this isn't what is seen in the experiment.
So, it is pretty safe to say physicists have thought this through.
To add more, you could seperate the slits from each other.
Also, try answering why a region(of minimum intereference) that was receiving tennis balls when one slit was open, would stop receiving tennis ball if the second slit got opened.
A: Your explanation makes no sense. To see why, suppose you have two slits and you record a particular interference pattern as a result: a series of light and dark bars. If you then cut an additional pair of slits half way between the first pair of slits, the resulting pattern may have some dark bars where formerly there were light bars. The only way this can be explained is if there is something going through the additional slits that deflects the light that would have hit the bars that were light in the two slit experiment. A full explanation of this point can be found in "The Fabric of Reality" by David Deutsch, Chapter 2.
A: Your explanation has a tennis ball that is a body and you are influencing it with forces , but in reality particles like electrons , photons even complete atoms show this behavior because everything behaves like a wave of some wavelength , it is just that as the particles become macroscopic , the effect is minimized .
The "famous photo" when you notice is just like a wave where the white regions being crest and the dark being the trough
