I don't believe it...
I can't believe this crap is patentable.
Spelling checkers work now by finding words that have a few similar characters in, generally somewhere near in the alphabet or phonetically.
Finding a replacement character that is nearby on the keyboard doesn't seem to be too big a leap intellectually and something I've been cursing about the lack of ever since I started using a "soft" keyboard.
Surely it needs nothing to do with a "pattern of dots". Simply take the 8 characters surrounding each typed character and search each of them through the valid word database. I'm guessing there would only be a couple of matches, (bearing in mind the design of qwerty was that normal English would have minimal striker collisions on an old mechanical typewriter running at speed.)
I expect indexing could be clever enough to narrow down most words after only a few characters.