How to do mathematically accurate Venn diagrams in Excel 2007

Question: How to do mathematically accurate Venn diagrams in Excel 2007 (as distinct from the ones in Smart Art)

Answer:  Widely discussed question on the web – there doesn’t appear to be a plug in for this

Looked in the Office Marketplace but couldn’t find anything close (The office marketplace also lacks decent search tools, so I might have missed it…)

There is an article on mathematically accurate Venn diagrams – which details building them up step by step at http://blog.data-miners.com/2008/10/creating-accurate-venn-diagrams-in.html

I haven’t tried it – but it looks like it would work.

Steven