30-sided dice roll 0 through 9 on a curve. When rolling, you are 5-times more likely to get a 4 or 5 than 0 or 9

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updated November 6, 2023

TLDR: These 30-sided dice roll 0 through 9 on a curve. When rolling the dice, you are 5-times more likely to get a 4 or 5 than you are to get a 0 or 9.

Here is the exact probability graph, created using anydice.com:

I was able to resin print it fairly small (just under 20mm, which is smaller than most d20) with relatively few defects. Making it a bit larger (25mm, closer to a d20) would likely help hide defects caused by the supports.

Painting was fairly easy. I fount it worked great to rub paint into all the numbers using a paper towel, then after 5 to 10 min of drying, polish the die with a damp magic eraser to remove excess paint and get a nice glossy shine. (attached a picture of my first print/paint below):

The die is mathematically balanced. Half of the 5-face vertices sum to 21, with the other half summing to 22. The 3-face vertices sum to 13 and 14, also split half and half. Mathematically speaking, the die is equivalent to rolling (d5+d6-2), getting a similar effect to rolling two dice, but with the addition being built into the die itself.

You never know how far you'll fall down the statistics/probability rabbit hole till you try…

The author marked this model as their own original creation.