Geometric composition involving equilateral triangles

## IXOHOXI Magic Square

The neat magic square featured on this stamp was created by Brazilian mathematician Inder Taneja. This square, called IXOHOXI magic square, not only shows common properties like other magic squares, as well as being pandiagonal, but also include extra properties such as symmetries, rotations and reflections.

## Shortest Path on a Cube

## The Paradox of Infinity

## Magic Inscribed Lotus

Indian mathematician Nārāyaṇa (1356) is the originator of the “Inscribed Lotus” (*Padma Vrtta*, a magic diagram constructed with the numbers of the 12×4 magic rectangle), in which every group of 12 numbers has the same sum **294**.

## A Paradoxical Zero-Length Hypotenuse

A strange right-triangle involving the unit imaginary number *i*

## Sacred Geometry

Repeated barycentric subdivision results in a gorgeous fractal-ish pattern.

## Toeplitz’ Conjecture

## Six Points on a Circle

Take 6 points on a circle such that every second edge (green chords) has length equal to the radius of the circle. Then the midpoints of the other three sides of the cyclic hexagon form an equilateral triangle.

Read more: https://www.archimedes-lab.org/2-Sunday_puzzle_43.html

## Geometric Passe-muraille

A 3D regular hexahedron solid (cube) passing through a 2D plane: