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We propose a novel class of spirals that are based on perfect polygonal formations. The spirals are defined by a fractal of right triangles that delineate their geometry and determine their progression rates and modes. We show how these…

General Mathematics · Mathematics 2021-11-05 Robert E. Grant , Talal Ghannam , Amanda Kennedy

We present experimental measurements on the spontaneous formation of compact spiral structures in vertically-vibrated granular chains. Under weak vibration, when the chain is quasi two-dimensional and self-avoiding, spiral structures emerge…

Soft Condensed Matter · Physics 2007-05-23 R. E. Ecke , Z. A. Daya , M. K. Rivera , E. Ben-Naim

A flipturn is an operation that transforms a nonconvex simple polygon into another simple polygon, by rotating a concavity 180 degrees around the midpoint of its bounding convex hull edge. Joss and Shannon proved in 1973 that a sequence of…

Let a polygon be composed of equal rectangles. We find all quadratic irrationals r for which the polygon can be tiled by similar rectangles with given side ratio r.

Combinatorics · Mathematics 2021-11-29 Ivan Novikov

For every $n$, we construct two curves in the plane that intersect at least $n$ times and do not form spirals. The construction is in three stages: we first exhibit closed curves on the torus that do not form double spirals, then arcs on…

Combinatorics · Mathematics 2024-06-11 Jan Kynčl , Marcus Schaefer , Eric Sedgwick , Daniel Štefankovič

In contrast to many known results concerning periodic tilings of the Euclidean plane with pentagons, here tilings with rotational symmetry are investigated. A certain class of convex pentagons is introduced. It can be shown that for any…

Metric Geometry · Mathematics 2025-07-02 Bernhard Klaassen

We describe new methods for the construction of spiral toolpaths for high-speed machining. In the simplest case, our method takes a polygon as input and a number $\delta>0$ and returns a spiral starting at a central point in the polygon,…

Computational Geometry · Computer Science 2015-01-21 Mikkel Abrahamsen

We give an elementary construction of polyhedra whose links are connected bipartite graphs, which are not necessarily isomorphic pairwise. We show, that the fundamental groups of some of our polyhedra contain surface groups. In particular,…

Combinatorics · Mathematics 2007-05-23 Alina Vdovina

A polygonal complex in euclidean 3-space is a discrete polyhedron-like structure with finite or infinite polygons as faces and finite graphs as vertex-figures, such that a fixed number r of faces surround each edge. It is said to be regular…

Metric Geometry · Mathematics 2009-06-08 Daniel Pellicer , Egon Schulte

An unfolding of a polyhedron is produced by cutting the surface and flattening to a single, connected, planar piece without overlap (except possibly at boundary points). It is a long unsolved problem to determine whether every polyhedron…

Computational Geometry · Computer Science 2007-05-23 Mirela Damian , Robin Flatland , Joseph O'Rourke

Skeletal polyhedra are discrete connected structures consisting of finite (planar or skew) or infinite (linear, planar, or spatial) polygons as faces, with two faces on each edge and a circular vertex figure at each vertex. The present…

Combinatorics · Mathematics 2026-02-24 Egon Schulte , Tomas Skacel

A grid polygon is a polygon whose vertices are points of a grid. We define an injective map between permutations of length n and a subset of grid polygons on n vertices, which we call consecutive-minima polygons. By the kernel method, we…

Combinatorics · Mathematics 2007-05-23 Toufik Mansour , Simone Severini

We examine a class of geometric theorems on cyclic 2n-gons. We prove that if we take n disjoint pairs of sides, each pair separated by an even number of polygon sides, then there is a linear combination of the angles between those sides…

Computational Geometry · Computer Science 2024-01-25 Philip Todd

This paper studies the straight skeleton of polyhedra in three dimensions. We first address voxel-based polyhedra (polycubes), formed as the union of a collection of cubical (axis-aligned) voxels. We analyze the ways in which the skeleton…

Computational Geometry · Computer Science 2008-05-02 Gill Barequet , David Eppstein , Michael T. Goodrich , Amir Vaxman

We construct helicoid-like embedded minimal disks with axes along self-similar curves modeled on logarithmic spirals. The surfaces have a self-similarity inherited from the curves and the nature of the construction. Moreover, inside of a…

Differential Geometry · Mathematics 2014-04-30 Christine Breiner , Stephen J. Kleene

Given vertex valencies admissible for a self-dual polyhedral graph, we describe an algorithm to explicitly construct such a polyhedron. Inputting in the algorithm permutations of the degree sequence can give rise to non-isomorphic graphs.…

Combinatorics · Mathematics 2021-08-03 Riccardo W. Maffucci

We construct compact polyhedra with $m$-gonal faces whose links are generalized 3-gons. It gives examples of cocompact hyperbolic bildings of type $P(m,3)$. For $m=3$ we get compact spaces covered by Euclidean buildings of type $A_2$.

Combinatorics · Mathematics 2007-05-23 Alina Vdovina

We construct embeddings of simplicial complexes into a (surface of a) simplicial ball whose triangulation has bounded degrees and low volume. This construction can be used either to efficiently "simplify a complicated space" by realizing it…

Geometric Topology · Mathematics 2022-11-29 Aleksandr Berdnikov

We give a tight upper bound on the polygonal diameter of the interior, resp. exterior, of a simple $n$-gon, $n \ge 3$, in the plane as a function of $n$, and describe an $n$-gon $(n \ge 3)$ for which both upper bounds (for the interior and…

Combinatorics · Mathematics 2010-12-17 Yaakov S. Kupitz , Horst Martini , Micha A. Perles

We investigate the ``generalized Heron polynomial'' that relates the squared area of an n-gon inscribed in a circle to the squares of its side lengths. For a (2m+1)-gon or (2m+2)-gon, we express it as the defining polynomial of a certain…

Metric Geometry · Mathematics 2007-05-23 F. Miller Maley , David P. Robbins , Julie Roskies