Let me do it in the same color. So the slope in this direction, that's the partial derivative with respect to m, is going to be flat. It's not going to change in that direction. And the partial derivative with respect to b is going to be flat. So it will be a flat point right over there. The slope of that point in that direction will also be 0, and that is our minimum point. Let's figure out the m and b's that give us this.