Their are three misteaks in this sentence.

A sentence which on first inspection only appears to have two mistakes (their and misteaks). Apparently, this miscalculation is supposed to be the third mistake. Thus is the sentence vindicated. Of course, in doing so I am assuming that three misteaks means three mistakes even before I've corrected it. Thus is the verdict repealed. Or is it?

I came across this sentence and many more of its self-referential brethren in a book by Douglas Hofstadter: Metamagical Themas (1996 Basic Books)