Quote:
Originally Posted by zsero
There is a point what I think is not clearly explained. It took me a long time to realize that it's not true that exactly one point gets corrected in each step. The true statement is that at most one point gets corrected in each step.

The "at most" part may also be tricky, because you may be using point A for correction but "happens" to correct B and C by moving in a good direction.