America built three big, bold and beautiful bridges during a period of only 6 years. In 1931, the George Washington Bridge leaped the Hudson River and linked Manhattan to New Jersey. That same year brought us the Bayonne Bridge linking Staten Island to New Jersey and in 1937 San Francisco’s Golden Gate Bridge opened.
Three astounding inventions that changed our world each occurred about one hundred years apart from one another. For thousands of years, until about 1750, the only way to make things move was with human muscle, animal muscle, wind or moving water. Then the steam engine appeared which could perform vastly more work than the work originally needed to obtain the coal to fuel it. For thousands of years the fastest way to communicate information was to send a man on a horse. About a hundred years after the invention of the steam engine, in 1844, Samuel Morse sent an electronic message down a copper wire from the Capitol in Washington DC to Penn Station in Baltimore. In 1948 William Shockley at Bell Labs invented the transistor making possible the digital world we take for granted today.
Three revolutions help us understand the American War of Independence: the English Civil War of 1643, the French Revolution in 1789 and the Russian Revolution in 1917.
The three previous paragraphs are intended to demonstrate a truism of successful speaking and writing. Our attention tends to be attracted and retained by a list of three items. I could have added the San Francisco Oakland Bay Bridge to the first paragraph; it was opened in 1936. I could have added the invention of the airplane by the Wright Brothers in 1903 to the second paragraph. I could have added the Mexican revolution of 1910 to my third paragraph. However, in each paragraph, I deliberately wanted three items.