They describe the new pound coin as twelve-sided; the original plan for the Susan B. Anthony dollar coin was eleven-sided. Lobbying by the coin machine industry led to its redesign as a standard circular coin with an inscribed undecagon. The SBA dollar only lasted a few years, partly because it was almost the same size as the quarter, and the polygonal shape that was supposed to make it distinguishable had been abandoned.
That and it was a pretty ugly coin. I’ve read that the designers at the mint tried to soften up Susan B’s features but her family insisted on portraying her as she was. Even the more pleasant-looking Sacagawea dollar with its “gold” color hasn’t made much of a dent in circulation.