A motorcycle or motorbike is a single-track, two-wheeled motor vehicle powered by an engine. Styles of motorcycles vary depending on the task for which they are designed, such as long distance travel, navigating congested urban traffic, cruising, sport and racing, or off-road conditions. In many parts of the world, motorcycles are among the least expensive and most widespread forms of motorised transport. Motorcycles must be leaned in order to turn. This lean can be induced by a method known as countersteering, in which the rider turns the handlebars in the direction opposite of the desired direction of turn. In other words, press forward on the handgrip in the desired direction—press right to go right, press left to go left. This concept is counter-intuitive and often very confusing to novices—and even to many experienced motorcyclists.[9] Short wheelbase motorcycles, such as sport bikes, can generate enough torque at the rear wheel and enough stopping force at the front wheel to lift the other wheel off the pavement. These actions, if performed on purpose, are known as wheelies and stoppies respectively. If carried past the point of recovery the resulting upset is known as "looping" the vehicle. Different types of motorcycles have different dynamics and play a huge role in how a motorcycle performs in given conditions. For example, a shorter wheelbase would generally make a bike lean faster and would be quicker around corners compared to a longer wheelbase.[citation needed] Longer wheelbase on the other hand provides more stability in a straight line.

Rings

A finger ring is a circular band worn as a type of ornamental jewelry around a finger; it is the most common current meaning of the word ring. Other types of metal bands worn as ornaments called rings, such as arm rings and neck rings. Rings worn by both men and women and can be of any quality. Various ring shapes and styles exist. The following are but a few. Flat wedding bands are the simplest form of ring. A flat wedding band consists of a strip of metal bent around into a loop and joined where the ends meet. Half-round rings, also called D-shape rings, are flat wedding bands filed half-round on the outside. Sleeve rings are rings that consist of a thin inner ring or sleeve, with several other rings stacked onto it to form one solid ring. Either the rings soldered onto the sleeve or the ends of the sleeve can be upset to keep them all together. A little of both can also be done. Solitaire rings are rings with a single large stone as a centerpiece, usually a diamond. Eternity rings are rings with stones, usually diamonds, of the same cut and size, set in one row all around the ring. The stones are usually round or square, and the setting is usually either claws or a channel setting. When the stones do not continue around the entire ring, but stop halfway around the finger, it is a half-eternity ring. Trinity rings or Trilogy Rings are three rings worn at one time. Cluster rings are rings with a group of stones in a cluster setting, forming the focal point of the ring. The cluster setting usually consists of one large stone in the center surrounded with several smaller stones. Tension Rings are a type of ring in which a single gemstone is held in place by pressure rather than prongs, a bezel or other mounting. The metal setting is actually spring-loaded to exert pressure onto the gemstone. In the United States and Canada, ring sizes specified using a numerical scale, with quarter and half sizes. An increase of a full size is an increase of 0.032 inch in diameter, or roughly 1/10 inch in inside circumference. Generally, sizes in quarters and halves will not relate conventionally to anything on any known ruler. On one finger alone, a person may vary more than a whole ring size- depending on time of day, work performed, and other swelling-inducing activities/conditions. Therefore, in most cases quarter-sizes are meaningless unless one needs precise accuracy with a particular ring.