Thread Question

[Duncan Booth]

Simon Forman wrote:

> If you need help understanding it please ask questions.  I, for one,
> would be happy to comment it for you to explain how it works.  It's so
> nice and elegant that I've already cut-and-pasted it into my own
> "notebook" of cool useful python "patterns" to use in the future.
> 
> Reread it slowly, think about what it's doing, if questions arise write
> them down and ask them.  Duncan's code is beautiful.  It's well worth
> your time to understand it.

If you convert what I wrote into an example which actually runs then do 
repost it. It might also be easier to understand since I'm sure I'll have 
made some mistakes or omitted some critical bits (such as the import 
lines).