Feedback loop that uses natural phenomena.
A feedback loops is an interesting version of a loop. Instead of just repeating an action over and over again, a feedback loop uses the output of the loop as input in the next round. So the input defines the output, which defines the input, which defines the output and so on. Feedback loops are used in algorithms (for instance the filter bubble is a feedback loop), however feedback loops are also present in nature: the food chain, water cycle and climate are great examples. Nature is filled with these complicated, yet seemingly simple phenomena, which raised the question: is it possible to design a feedback loop with nature?
Photosynthesis is a relatively well-known given in nature. A plant uses light and CO2 to create glucose as a nutrient, while creating oxygen as a by-product. Another by-product it produces is electricity. The degree of photosynthesis that takes place in a plant is dependent on the colour of the light: red light means more photosynthesis and more generated electricity, while blue light means less photosynthesis and less generated electricity.
By using the plant as a sensor the generated electricity is measured. The amount of generated electricity determines the colour above one of the other two plants, which determines the degree of photosynthesis in this plant, which determines the amount of generated electricity in this plant, which determines the colour above the third plant, which controls the light en therefor the generated electricity of the first plant, hereby creating a feedback loop.