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
Rackets (sport) covered racket court and is now the oldest surviving court in the world, as well as being the oldest indoor sports building in Scotland. It has been restored as a racket hall, but used as an exhibition area. Some private clubs also built courts. Along with real tennis and badminton, rackets was used as an inspiration for the game of lawn tennis, invented in 1873 by Walter Clopton Wingfield. A vacant rackets court built into the University of Chicago's Stagg Field served as the location of the first artificial nuclear chain reaction on December 2, 1942. The Stagg Field court