Violin construction and mechanics four open strings, usually tuned to G, D, A, and E. The strings run from a tailpiece attached to the base, across a wooden bridge, continue towards the neck of the instrument running parallel to the fingerboard, and connect to the pegbox located at the very top of the violin. They are wound around four tuning pegs that are mounted sideways through holes in the pegbox. The bridge helps to hold the strings in place, while the pegs maintain the tension necessary to produce vibration. Strings were first made of sheep's intestines (called "catgut"), stretched, dried and twisted. Contrary to
Tennis the modern game, rackets were made of wood and of standard size, and strings were of animal gut. Laminated wood construction yielded more strength in rackets used through most of the 20th century until first metal and then composites of carbon graphite, ceramics, and lighter metals such as titanium were introduced. These stronger materials enabled the production of oversized rackets that yielded yet more power. Meanwhile, technology led to the use of synthetic strings that match the feel of gut yet with added durability. Under modern rules of tennis, the rackets must adhere to the following guidelines; The rules regarding