are sometimes seen. Brakes are also commonly used, and most soap-box cart racing contests require these. Often a simple friction brake operated by a lever which bears on one of the tyres is all that is required under the rules. Gravity racer carts are unpowered, and are either pushed by willing helpers, or are run down a suitable slope. Races will usually take place downhill and the most efficient and skillfully driven cart will win - gravity applying equally to all. Gravity racer carts also make great construction projects for children, requiring only an intuitive sense of engineering, and a few basic construction skills. There are also predesigned kits available, though for many this defeats the purpose of the exercise. Recently, more advanced gravity racers are beginning to emerge. These, intended for competition in the major soapbox races, are sometimes made of carbon fibre and feature a monocoque design, although most use a more traditional chassis or spaceframe design with bodywork made from materials such as plywood, corrugated plastic or similar. Examples of such soapboxes include the Lotus 119c and the Formula Gravity VXR Nimbus. In Australia billy carts tend to conform, even in the 21st century, to a more traditional or rudimentary specification often being constructed informally by juveniles from found or inexpensive materials with minimal adult input and used without safety equipment. However even when construction of vehicles is more formally organised, such as for the annual Blacktown and District Cub Scout Billy Cart Derby at Rooty Hill, NSW the vehicle is still constructed to a deliberately relatively unsophisticated design, although safety is a consideration. In Indonesia, billy carts are also known as 'gokar'. They are raced in different regions as a community social activity. The form of the cart is similar to the Australian one. However, the wheels are often motor cycle wheel bearings. In Brazil, gravity racers are known as "carrinhos de rolimã." Traditional designs are very minimalistic, with an open board-like body and wheels made up of naked ball bearings (no tyres allowed), usually discarded parts obtained from auto mechanics. Electric soapboxes are a new development and are not, in fact, pure gravity racers since they are electrically powered. History of gravity racer races The first recorded gravity race took place in 1904 in Oberursel (Taunus) near Frankfurt, Germany. It was inspired by major motor sports events like the Gordon Bennett Cup and the Kaiserpreis