Concave Pyramids of Second Sort -The Occurrence, Types, Variations
Abstract
Correspondingly to the method of generating the Concave Cupolae of second sort, the Concave Pyramids of second sort have the similar logic of origination, and their counterpart in regular faced convex pyramids (tetrahedron, Johnson's solids J1 and J2). The difference is that instead of onefold series of equilateral triangles in the lateral surface of the solid, there appear twofold series, forming deltahedral lateral surface with a common point, while bases are also regular polygons. This time, instead of the bases from n=3 to n=5, there are the basis from n=6 to n=9. The same lateral surface’s net can be folded and creased in two different ways, which produces the two types of Concave Pyramids of second sort: with a major and with a minor solid height. Combining and joining so obtained solids by the correspondent bases, the concave (ortho) bipyramids of second sort emerge, which then may be elongated, gyroelongated, and conca-elongated, creating a distinctive family of diverse concave... polyhedral structures.
Source:
Proceedings. Vol. 2 / 4th International Scientific Conference on Geometry and Graphics moNGeometrija 2014, June 20th - 22nd, 2014 Vlasina, Serbia, 2014, 157-168Publisher:
- Faculty of Civil Engineering and Architecture ; Serbian Society for Geometry and Graphics SUGIG, Niš ; Beograd
Funding / projects:
- Development of new information and communication technologies, based on advanced mathematical methods, with applications in medicine, telecommunications, power systems, protection of national heritage and education (RS-MESTD-Integrated and Interdisciplinary Research (IIR or III)-44006)