When I was in Egypt several years ago, I saw tomb paintings of oxen pulling wooden plows. The thing that made that remarkable is that, 4,000 years later, in the 1850s in the United States, plowing was still done by oxen pulling wooden plows. While the blacksmith named John Deere did not replace the oxen or the wooden plows, he created a self-cleaning steel plowshare that could cut through the impossibly tough sod of the prairies. (For those of you who may not be familiar with plows, the plowshare is the part at the front that cuts into the soil.)
Here is a reproduction of that 1837 John Deere plow, displayed at the John Deere Pavilion in Moline.