If I have $2$ vector points and I wish to create a 3rd vector point to make a plane from.
I'd like to make sure the 3rd point I generate doesn't happen to have the same slope.
I can add either $1$ to $y$ or one to $x$ to create it but it might by chance be that this new point is one the line made by point $A$ and $B$ and so therefore not really a plane.
I think I can take the slope of $A \to B$ and normalize it. I should be able to compare that to my slope of $A \to A + X$ which is of course a slope of $X$ and so if the slope of the two lines is equal, I just add the other direction instead.
Does that sound mathematically correct?