Indeed, it's not ambiguity, but visually a bit confusing. ("Visual ambiguity"? Certainly not in meaning.) But simonb, targeting the document at that audience doesn't have to come at the expense of the Scheme-experienced; after all, a trivial change "foo" to "bar" (#\f to #\b) would remove the confusion. As an aside, I doubt "readers with little programming experience" would be reading the tutorial for a pre-alpha language.
