So what do we have at birth? So basically, the ductus arteriosis does not close. Yet we have a higher pressure inside the order, which is part of the circulatory system, than inside the pulmonary trunk, which is part of the pulmonary circulatory system. And what will happen is that blood, the fluid, will move down its pressure gradient from the order and into the pulmonary trunk because now we have a higher pressure inside the order compared to our pulmonary trunk. And so our blood, the oxygenated blood, will travel from the order into the pulmonary trunk. And so we have a mixing of oxygenated and deoxygenated blood taking place within the pulmonary trunk.