- Star Tales - Circinus (ianridpath.com)
An insignificant constellation representing a pair of dividing compasses as used by geometers, draughtsmen, and navigators for drawing circles and measuring distances; they are also known as dividers. Circinus was introduced in the 1750s by the Frenchman Nicolas Louis de Lacaille, who fitted various figures into gaps between the existing constellations of the southern skies. In this case the gap seems to have been almost non-existent, and the compasses are squeezed in their folded position between the forefeet of Centaurus and Triangulum Australe. It is the smallest of Lacaille’s 14 inventions, and the fourth-smallest constellation in the entire sky.
- Square (Wikipedia)
In Euclidean geometry, a square is a regular quadrilateral, which means that it has four equal sides and four equal angles (90-degree angles, π/2 radian angles, or right angles). It can also be defined as a rectangle with two equal-length adjacent sides. It is the only regular polygon whose internal angle, central angle, and external angle are all equal (90°), and whose diagonals are all equal in length. A square with vertices ABCD would be denoted ◻ ABCD.
