"The key point about a demonstration is that it must be seen. Hence the term "demonstration." If a person demonstrates privately in his own home, this is not technically a demonstration but merely "acting silly" or "behaving like an ass."

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There is no character, howsoever good and fine, but it can be destroyed by ridicule, howsoever poor and witless. Observe the ass, for instance: his character is about perfect, he is the choicest spirit among all the humbler animals, yet see what ridicule has brought him to. Instead of feeling complimented when we are called an ass, we are left in doubt.

— Mark Twain