Water Plumber
Your friend needs water, and you are a plumber trying to cool him spend pipe with water. To do this you need to add up the pieces of the pipeline from one part of the tube to the other, so that the water flowed to your friend.
Your friend needs water, and you are a plumber trying to cool him spend pipe with water. To do this you need to add up the pieces of the pipeline from one part of the tube to the other, so that the water flowed to your friend.