I think a lot of the most beautiful things humans have done, have either been copies of nature, or by accident.

Looking from high over a city at night is one thing, and these dry stone walls which criss cross the UK are another.

It always amazed me the amount of human effort that must have gone into the many thousands of miles of them.  Then over time, the cracks became homes for things, plants, insects, animals.

Here is one which shows you the typical beauty of them.