The Eleven-Faced Die That Emulates Two Six-sided Dice

Rolling two six-sided dice (2d6) gives results from 2 to 12 with a bell curve distribution. Seven being the most common result, two and twelve being the least common. But what if one could do this with a single die?

This eleven-sided die has a distribution matching the results of 2d6.

As part of research Putting Rigid Bodies to Rest, researchers show that a single eleven-sided asymmetric shape can deliver the same results. That is to say, it rolls numbers 2 to 12 in the same distribution as 2d6. It’s actually just one of the oddball dice [Hossein Baktash] and his group designed so if you find yourself intrigued, be sure to check out the 3D models and maybe print your own!

The research behind this is a novel method of figuring out what stable resting states exist for a given rigid body, without resorting to simulations. The method is differentiable, meaning it can be used not just to analyze shapes, but also to design shapes with specific properties.

For example, with a typical three-sided die each die face has an equal chance of coming up. But [Hossein] shows (at 8:05 in the video, embedded below) that it’s possible to design a three-sided die where the faces instead have a 25%-50%-25% distribution.

How well do they perform in practice? [Hossein] has done some physical testing showing results seem to match theory, at least when rolled on a hard surface. But we don’t think anyone has loaded these into an automated dice tester, yet.

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ATtiny Hacks: Roll 2d6 With An ATtiny

A pair of 6-sided electric dice (original in Dutch, here’s the Google Translate link) was sent in on the tip line for our ATtiny hacks theme. We really appreciate the simplicity of the circuit; it really shows how the complexity of discrete components can be cut down with a simple microcontroller.

The circuit is very simple – An ATtiny26 serves as the core of the project. Fourteen LEDs are connected to fourteen pins on the micro. The tiny26 might be a bit overkill. With Charlieplexing, we suspect this build could have been completed with an 8-pin micro like an ATtiny25. The code for the build (written in BASIC with BASCOM-AVR), board files and schematics have all been posted.

We’ve seen a few electronic dice builds before. this build uses an ATmega328 in a hugely overwrought circuit. Compared to what can be done with a 555, the ATtiny26 build provides a very nice middle ground.

Thanks [Roeland] for sending this in.