Vessel diameter changes blood pressure. The viscosity of the blood or yeah, the blood. And now you said the vessel length changes the blood pressure. So if we were to lengthen the hose, that five liters per minute needs to now work its way through a longer length of hose,. which means there's more resistance it's encountering. In this scenario, let's just say we've got a kilometer of blood vessels, right? As that blood moves through, the more vessel wall it experiences, the more resistance it experiences. and so it's harder to move through. It continues to back up into the heart and heart goes, oh my God, there's more after