[metapost] Drawing a urn

[Hartmut Henkel]

On Thu, 29 Nov 2007, Troy Henderson wrote:

> > yes, which leads to other implementations: put exactly as many black
> > balls in as needed, but place them randomly (avoiding collisions),
> > or e. g. put balls first in regularly and then stir them up randomly
> > (e.g. repeatedly exchanging balls between two random positions.
>
> Is that what your posted code does?

no, but Dan's does it, admirably (modulo typos :-)

Regards, Hartmut