What is a regular tetragon?

Paul revere :)

A regular polygon has all sides of equal length, and all angles of the same measure. An irregular polygon does not fulfil these requirements.

Irregular

This is a tautological question that does not have a proper answer. A regular polygon is one which has all its sides of equal length and all its interior angles of equal measure.

There is such a thing as a regular heptagon, but it cannot be constructed under the rules of classical Greek construction. Any heptagon constructed under these rules will therefore be irregular. This...