Steve Shaw (or anyone else who enjoys a challenge): How would you punctuate (and/or capitalize, italicize, etc.) the following sentence?
there are four is in mississippi
—or, if that doesn't make sense to you—
there are four ss in mississippi

I would apply common sense by writing the sentences as follows: "The letter 'i' occurs four times in 'Mississippi'. The letter 's' occurs four times in that word too." At first sight my alternatives seem longer and more laboured, but just consider the time saved by the recipient in not having to do the mental processing required to work out what I mean. Good English is not just about common sense; good manners enter into the equation too.