A fence is a structure that encloses an area, typically outdoors, and is usually constructed from posts that are connected by boards, wire, rails or netting. A fence differs from a wall in not having a solid foundation along its whole length.

Alternatives to fencing include a ditch (sometimes filled with water, forming a moat).

https://en.wikipedia.org/wiki/Fence

"There are all kinds of interesting questions that come from a knowledge of science, which only adds to the excitement and mystery and awe of a flower."
Richard Feynman
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