This is a Cellular Automaton that I made. I call it "Respiration". There are 7 types of cells: Oxygen, Depleted, Carbon Dioxide, Vessel, Lung, Component and Empty. Here's how it works: Rule 1: If there is an Empty cell next to an Oxygen cell, the Empty cell will turn Oxygen. Rule 2: Oxygen turns into Depleted. Rule 3: Depleted turns into Carbon Dioxide. Rule 4: Carbon Dioxide turns into Empty. Rule 5: A Vessel cell will always be a Vessel cell, same with Lung and Component. Rule 6: If a Carbon Dioxide cell touches a Lung cell, it turns into Oxygen. Rule 7: If an Oxygen cell touches a Component, it will turn into Carbon Dioxide.