10 most difficult in­ven­tors riddles

On May 15, 1718, Englishman James Puckle patented his machine gun, the world's first! You may have thought the Gatling gun or the Maxim machine gun was the first machine gun, but depending on how you define “machine gun” James Puckle, Esq. (yes, he was a lawyer) got there first.

Mary Anderson (1866 -1953) was an American real estate developer, rancher, viticulturist and inventor of the windshield wiper blade. In November 1903 Anderson was granted her first patent for an automatic car window cleaning device controlled from inside the car, called the windshield wiper. In 1922, Cadillac became the first car manufacturer to adopt them as standard equipment.

The oldest documented violin to have four strings, like the modern violin, is supposed to have been constructed in 1555 by Andrea Amati. Earlier instruments only had three strings and were called violetta. The violin immediately became very popular, both among street musicians and the nobility.

Charles Goodyear for many years improved the method of hardening the rubber. When he succeeded in 1839, investors were already offended by earlier failures. Charles died in misery. The Goodyear company was named in his honor, but otherwise is not related to him.

Samuel Colt missed a great opportunity in firearms development when he dismissed an idea from one of his gunsmiths, Rollin White. White proposed a "bored-through" revolver cylinder to allow the use of metallic cartridges in a handgun. After Colt fired White for suggesting an improvement to his revolver, White took his idea to Colt's competitor, Smith & Wesson, who patented his invention and kept Colt from being able to build cartridge firearms for almost 20 years.

Margarine was invented in France by Hippolyte Mège-Mouriès in 1869, during the Franco-Prussian wars. He invented it in response to a competitive challenge from the French government under Napoleon III, who was looking for a cheap and stable substitute for butter, and offered a big prize to anyone who could pull it off.

Jan Koum is a Ukrainian American computer programmer. In January 2009, Koum bought an iPhone and realized that the then seven-month-old App Store was about to spawn a whole new industry of apps. He visited his friend Alex Fishman and the two talked for hours about Koum's idea for an app. Koum almost immediately chose the name WhatsApp because it sounded like "what's up", and a week later on his birthday, February 24, 2009, he incorporated WhatsApp Inc. in California.

Daniel Gabriel Fahrenheit was a German physicist, engineer, and glass blower who is best known for inventing the mercury-in-glass thermometer (1714), and for developing a temperature scale now named after him

Marconi was credited to be the first radio constructor, but in 1943 the US Supreme Court has granted patent rights to Tesla patent. Marconi admitted he was using Tesla's work in his construction.

A Nipkow disk is a mechanical, rotating, geometrically operating image scanning device, patented in 1885 by Paul Gottlieb Nipkow. This scanning disk was a fundamental component in mechanical television through the 1920s and 1930s.