出典:Wikipedia
出典:『Wikipedia』 (2011/06/06 15:19 UTC 版)
A tri-oval is a shape which derives its name from the two other shapes it most resembles, a triangle and an oval. Rather than meeting at sharp, definable angles as the sides of a triangle do, in a tri-oval these angles are instead rounded into smooth curves. While an oval has four turns, a tri-oval has an "extra" fifth turn. This term is most often used to describe the shape of many automobile racetracks, including: