I like the idea in theory, but there's a few of practical issues<p>1) I got the circle, and I tried 8 times before giving up. I was pretty damn close but it just denied me. There seems to be more lenience in the straight line options, perhaps just stick to them.<p>2) What's the fallback for blind users?<p>3) There are 16 images that are used, and you can have as many guesses as you want. I'm guessing that it's easily brute forced. How about dynamically generate a shape from n lines?