<P> Meanders are sinuous bends in rivers or other channels, which form as a fluid, most often water, flows around bends . As soon as the path is slightly curved, the size and curvature of each loop increases as helical flow drags material like sand and gravel across the river to the inside of the bend . The outside of the loop is left clean and unprotected, so erosion accelerates, further increasing the meandering in a powerful positive feedback loop . </P> <Ul> <Li> <P> Chaos: shell of gastropod mollusc the cloth of gold cone, Conus textile, resembles Rule 30 cellular automaton </P> </Li> <Li> <P> Chaos: vortex street of clouds </P> </Li> <Li> <P> Meanders: dramatic meander scars and oxbow lakes in the broad flood plain of the Rio Negro, seen from space </P> </Li> <Li> <P> Meanders: sinuous path of Rio Cauto, Cuba </P> </Li> <Li> <P> Meanders: sinuous snake crawling </P> </Li> <Li> <P> Meanders: symmetrical brain coral, Diploria strigosa </P> </Li> </Ul> <Li> <P> Chaos: shell of gastropod mollusc the cloth of gold cone, Conus textile, resembles Rule 30 cellular automaton </P> </Li> <P> Chaos: shell of gastropod mollusc the cloth of gold cone, Conus textile, resembles Rule 30 cellular automaton </P>

What is the most common shape in nature