The oldest known surviving example of a linear slide rule, which was made by inventor Robert Bissaker, dates to 1654. The standardized rectilinear design with scales familiar to us today is based on the Mannheim rule invented about 1853. Slide rules were originally made of brass, ivory or boxwood and later thermoplastics. The grid slide rule was invented by Joseph Everett in 1866. It is flat, rectilinear, and segmented into short parallel rules with an effective length of 40 feet. The Fuller calculator was introduced by George Fuller in 1878. It has an effective 42-foot long scale accurate to within 1 to 10,000 spiralled around a hand-held 3 inch diameter, 12 inch long wood tube. In 1881, Edwin Thatcher designed a tabletop slide rule that bears his name. It too is cylindrical, 4in. in diameter and 18in. long. One of the most popular pocket size, tubular styles, especially in Europe was the Otis King calculator which began production in 1922. The slide rule remained the basic tool of engineers and scientists until introduction of the hand held electronic calculator in 1971.