On Thu, 8 Feb 2001, Frank Mittelbach wrote:

> [...] or to remind you about the
> nice little article by Don Knuth  years back when he explained that he learned
> he was misusing the fact that digits in text and math when using CM fonts look
> the same so that his book Concrete math ended up looking horrible because
> there  digits for text were coming from concrete roman while those in math
> where coming from the euler fonts.

And all these time I liked the Concrete Mathematics look, and even found
this nice. Would you please tell me where the article is?