The flag of Cupertino is, unfortunately, one of those boring cases of logos on a bedsheet. The use of words and dates should be specially avoided in flags.
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The logo contains a morion, a kind of helmet here used to (anachronistiscally) represent the Spanish explorers that founded the city. It appears even in earlier version of city's seal.
The city is famous due to Apple, Inc., in turn famous, among other things, to the minimalistic design of its products. And, as a bit of minimalism is always welcome to flag design, here's my take:
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This depiction of a morion is present in USA Army heraldry.
Comments and suggestions are welcome.
Next week, a special post!