[extropy-chat] alt dot fair dice

[Spike]

> -----Original Message-----
> From: extropy-chat-bounces at lists.extropy.org 
> [mailto:extropy-chat-bounces at lists.extropy.org] On Behalf Of 
> "Hal Finney"
> Sent: Friday, October 08, 2004 9:50 PM
> To: extropy-chat at lists.extropy.org
> Subject: Re: [extropy-chat] alt dot fair dice
> 
> 
> Spike writes:
> > Can other shapes be made such that there is
> > equal probability of any face downward?  I can
> > think of one: a five sided pyramid shaped
> > solid (four triangular faces and one square
> > face)...
> 
> That's very interesting.  I remember watching people play Dungeons
> and Dragons when I was a kid, using many different kinds of fancy
> polyhedral dice.  I think they were all regular polyhedra, though.
> I haven't seen suggestions for fair, non-polyhedral dice...
> 
> Once upon a time I was pretty familiar with such formula, back in my
> math contest days, but it would take me a while to do it now, so if
> anyone else is motivated they might be able to come up with a 
> solution. Hal

I had an idea.  Back in the 70s we had a toy called
the superball.  I don't know if they are still available
but I don't see why they wouldn't be.  They were made
of a special high-elasticity rubber that would rebound
about 80% or more each bounce.

I think I can carve one of those to any shape with
a razor blade.  If I can estimate the proper shape by
a monte carlo simulation we could try to carve a
pyramid shaped die.  I might take a ride over to
ToysRUs tomorrow.  

Anyone with kids here know if superballs are still 
with us?  

spike