Here's my attempt... Never did quite get the bell curve (the edges still seem to get more balls than you'd expect) but this is pretty close. https://youtu.be/VTRIfe6UyiQ
HI Christopher,
This happens, because the pegs are too close together horizontally, compared to the vertical distances between the pegs A single ball would go either right or left, something (not even remotely) like this:
Because the opening is so wide, many balls fall at the same time and are bumping into each other, or can hardly move left or right and so the 'middle of the stream of balls' basically falls almost straight down, causing more balls to end up in the middle. There is ofcourse a lot more going on, with friction and so, but that's more or less my 'theory'.
Compare that with (not perfect either):
