Now, I take the ship, ship’s water line; let me draw the water line. You have learnt something about lines plan, so you know what a rule outline is, the plan of the rule outline you are aware. So, now, this, this is a pressure point we know because the slope starts, then suppose this went like, this continued like this forever, then this slope there is no other pressure point, there is only one pressure point unfortunately, we close it, we close the ship; so, when I bring it down like this I change the slope here again do you get it? in the ultimate, it is like, this is like a wedge, this as if it went like this and then it went straight, and then it went like this; if it went like this, there is a pressure point here, there is also a pressure point here, a negative pressure point, here also and here also do you understand, is that clear?