Not all groups of eubacteria have peptidoglycan, so all eubacteria may be classified as either Gram-positive (able to bind Gram's stain) or Gram-negative (unable to bind Gram's stain).
A portable DVD player is in the shape of a rectangular prism. A soccer ball is in the shape of a truncated icosahedron. These shapes are all examples of polyhedra. A three-dimensional shape whose faces are polygons is known as a polyhedron. This term comes from the Greek words poly, which means many, and hedron, which means face.. So, quite literally, a polyhedron is a three-dimensional object with many faces.
polygon. n. 1. (Mathematics) a closed plane figure bounded by three or more straight sides that meet in pairs in the same number of vertices, and do not intersect other than at these vertices. The sum of the interior angles is (n -2) Ã 180Â° for n sides; the sum of the exterior angles is 360Â°. A regular polygon has all its sides and angles equal. Specific polygons are named according to the number of sides, such as triangle, pentagon, etc. [C16: via Latin from Greek polugÅnon figure with many angles].