There are the natural cycles that flow through the streets of the city. The main are related to water, nutrients and energy. And there are man-made cycles related to the governance of the city, such as democracy, strategy and policy. They all relate to the core of public life, to resources, essentials and effects of decision making and city management. Cycles are essential in every ecosystem.
Water is the key source for life because all humans and communities need it: condensation – precipitation – collection – evaporation. Energy is key in all what we do: energy (solar) – production – fixation (plants) – consumption. Nutrient movement include that of carbon, sulfur, nitrogen, phosphorus, oxygen that continually recycle along with other mineral nutrients: production – allocation – consumption – decomposition.