Search results
Results from the WOW.Com Content Network
The tetractys is an equidistant and equiangular arrangement of ten points inside a triangle, akin to the fourth triangle number. It was developed by Pythagoras, and collectively signifies cosmic unity in the form of The Decad, as well as the musica universalis, or collective abstraction of the music generated by heavenly cosmic bodies.
The tetractys. The tetractys (Greek: τετρακτύς), or tetrad, [1] or the tetractys of the decad [2] is a triangular figure consisting of ten points arranged in four rows: one, two, three, and four points in each row, which is the geometrical representation of the fourth triangular number.
Truncated triangular trapezohedron, also called Dürer's solid: Obtained by truncating two opposite corners of a cube or rhombohedron, this has six pentagon faces and two triangle faces. [27] Octagonal hosohedron: degenerate in Euclidean space, but can be realized spherically. Bricard octahedron with an antiparallelogram as its equator. The ...
The smallest polyhedron is the tetrahedron with 4 triangular faces, 6 edges, and 4 vertices. Named polyhedra primarily come from the families of platonic solids , Archimedean solids , Catalan solids , and Johnson solids , as well as dihedral symmetry families including the pyramids , bipyramids , prisms , antiprisms , and trapezohedrons .
A truncated square is an octagon, t{4}={8}. A quasitruncated square, inverted as {4/3}, is an octagram, t{4/3}={8/3}. [2] The uniform star polyhedron stellated truncated hexahedron, t'{4,3}=t{4/3,3} has octagram faces constructed from the cube in this way. It may be considered for this reason as a three-dimensional analogue of the octagram.
The apparent triangles formed from the figures are 13 units wide and 5 units tall, so it appears that the area should be S = 13×5 / 2 = 32.5 units. However, the blue triangle has a ratio of 5:2 (=2.5), while the red triangle has the ratio 8:3 (≈2.667), so the apparent combined hypotenuse in each figure is actually bent. With the bent ...
Regular tetrahedra can be stacked face-to-face in a chiral aperiodic chain called the Boerdijk–Coxeter helix. In four dimensions , all the convex regular 4-polytopes with tetrahedral cells (the 5-cell , 16-cell and 600-cell ) can be constructed as tilings of the 3-sphere by these chains, which become periodic in the three-dimensional space of ...
Bipyramids, the duals of the infinite set of prisms, with triangle faces: any multiple of 4 (so that a face will face up), starting from 8; Disphenoids, an infinite set of tetrahedra made from congruent non-regular triangles: 4 sides. This is a less symmetric tetrahedron than the Platonic tetrahedron but still sufficiently symmetrical to be ...