Tangential quadrilateral all of whose sides are tangent to a single conic section has three diagonals that meet at a point. From a tangential quadrilateral, one can form a hexagon with two 180° angles, by placing two new vertices at two opposite points of tangency; all six of the sides of this hexagon lie on lines tangent to the inscribed circle, so its diagonals meet at a point. But two of these diagonals are the same as the diagonals of the tangential quadrilateral, and the third diagonal of the hexagon is the line through two opposite points of tangency. Repeating this same
Magic hexagon Magic hexagon A magic hexagon of order "n" is an arrangement of numbers in a centered hexagonal pattern with "n" cells on each edge, in such a way that the numbers in each row, in all three directions, sum to the same magic constant "M". A normal magic hexagon contains the consecutive integers from 1 to 3"n" − 3"n" + 1. It turns out that normal magic hexagons exist only for "n" = 1 (which is trivial, as it is composed of only 1 hexagon) and "n" = 3. Moreover, the solution of order 3 is essentially unique. Meng also