Tennis

Modern lawn tennis was invented in 1873 by British army officer Major Walter Clopton Wingfield, who devised a game called Sphairistike -- Greek for "playing at ball" -- blending elements of the older indoor game real tennis with racquets and the game of fives. He patented the game in February 1874, selling boxed sets that included a net, poles, rubber balls, and rules, and the new outdoor version was made possible by Charles Goodyear's rubber ball, which could bounce reliably on grass in a way traditional leather real-tennis balls could not.

Wingfield's original patented court was hourglass-shaped -- narrower at the net than at the baselines -- reportedly designed that way partly because the more sensible rectangular court layout was already in common use and couldn't be patented. Players quickly found the pinched shape impractical, since balls hit down the line escaped the narrow midsection, and the sport settled on a rectangular court by the time the first Wimbledon Championship was held in 1877.

A tennis court is built with two boundary widths already marked: 27 feet for singles and 36 feet for doubles, with the extra 9 feet split between two 4.5-foot doubles alleys running the length of the court on each side. Rather than using entirely separate courts, tennis simply adds side corridors that are in play only when a second player is covering that width -- a design that lets a single court surface host both formats without reconstruction.

The net height also changes subtly with position: it's higher at the posts (42 inches) than at the center strap (36 inches), a deliberate sag that makes cross-court shots down the middle marginally easier to clear than shots aimed at the corners near the posts.