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October 31 – 304.

The Kuen kabuki. In mathematics, a Zoll surface, named after Otto Zoll, is a surface homeomorphic to the 2-sphere, equipped with a Riemannian metric all of whose geodesics are closed and of equal length. The Kuen surface is a special case of Enneper’s negative curvature surfaces

Background: Hubble telescope. Galaxy Cluster MACS J0717, 5.4 billion light-years from Earth. It is one of the most complex galaxy clusters ever seen.

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June 29 – 180

Rhino 5.0. Geometric construction used by Hipparchus in his determination of the distances to the sun and moon. Hipparchus of Nicaea was a Greek astronomer, geographer, and mathematician. He was credited to be among the first mathematicians to divide the circle in 360 degrees of 60 arc minutes.

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June 28 – 179

Rhino 5.0. In geometry, when the angles opposite the equal sides of an isosceles triangle are themselves equal, the figure is known as the pons asinorum, (Latin for “bridge of donkeys”!) This statement, Proposition 5 of Book 1 in Euclid’s Elements, and is also known as the isosceles triangle theorem. Pons Asinorum is also the name given to a particular configuration of a Rubik’s Cube and used as a metaphor for finding the middle term of a syllogism.

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June 26 – 177

In finite geometry, a Fano plane is a finite projective plane of order 2, having the smallest possible number of points and lines, 7 each, with 3 points on every line and 3 lines through every point. This quasigroup template is being used in group theory construction and block design theory. It is named after Gino Fano, an Italian mathematician of the early 1900 who participated in the Klein encyclopedia of mathematical sciences.

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June 25 – 176

Rhino 5.0. Tangential trapezoid. In Euclidean geometry, a tangential trapezoid, is a trapezoid whose four sides are all tangent to a circle within the trapezoid. Every isosceles tangential trapezoid is bicentric. That particular shape was also found on a Japanese Sangaku.