What is remarkable about the scarlet letter Hester makes? What do you think Hawthorne is suggesting by having Hester make such a letter?

The letter is, as many things in Hawthorne, ambiguous.  Hester creates a symbol that recognizes the right of the society to punish her for a violation of its rules.  On the other hand she makes that symbol beautiful instead of the rag that one of the old maidens says it should be.  She makes it beautiful because she realizes that, although she violated a community standard, she did not violate her own:  "What we did had a consecration of it's own."  This ambiguity permeates most of Hawthorne's work (cf. "Young Goodman Brown"), and is beautifully handled here.