With or without water it can be used as a barrier, as an alternative for a fence.
A trench is a long narrow ditch.
Types and applications include:
... & B. F. Skinner
Science and Human Behavior[?]
The Shaping of a Behaviorist: Part Two of an Autobiography[?]
Skinner for the Classroom[?] by R. Epstein (Ed.) & B. ...
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