Retro wiki:

>Retro may also mean Retrorocket. Retro is a contemporary term used to describe things from a bygone era. It is often used in a positive sense, referring to quirky or attractive products that are no longer available. For example, "Retro fashion" or "Retro Chic" may consist of outdated styles, such as tie-dyed shirts from the 1970s, or poodle skirts from the 1950s. A love of retro objects (things from the past) is called retrophilia.
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Circle wiki:

>This article is about the shape and mathematical concept of circle; for other meanings, see Circle (disambiguation). In Euclidean geometry, a circle is the set of all points at a fixed distance, called the radius, from a fixed point, called the centre (center). The points can only be those that are part of a conic section; within the set of a plane bisecting a cone. Circles are simple closed curves, dividing the plane into an interior and exterior. Sometimes the word circle is used to mean the interior, with the circle itself called the circumference. Usually however, the circumference means the length of the circle, and the interior of the circle is called a disk or disc.
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