I think I am home and dry with this one, but a couple of things are causing me doubt. Firstly, there are several alternative ways of highlighting the buried item. I presume any of them would be acceptable. Secondly, I have found an entry wherein three letters could be changed to give the name of the famous exponent. However, one of the new words resulting from the changes is a proper noun and a rather obscure one at that. Does anyone else have the same issues?