Glossary of shapes with metaphorical names

Many shapes have metaphorical names, i.e., their names are metaphors: these shapes are named after a most common object that has it. For example, "U-shape" is a shape that resembles the letter U, a bell-shaped curve has the shape of the vertical cross section of a bell, etc. These terms may variously refer to objects, their cross sections or projections. In some disciplines, where shapes of subjects in question are a very important consideration, the shape naming may be quite elaborate, see, e.g., the taxonomy of shapes of plant leaves in botany.Summarize the following text using ONLY facts from it. Do NOT invent references, emails, or links. If the text doesn't mention something, leave it out. Use the weekly Newsquiz to test your knowledge of stories you saw on CNN.com or the CNN iReport app for a free, easy-to-use version of this article. See CNN.co.uk/Newsquiz for more information on how to use the Newsquitz app and the CNN App.