Rifle straps
My father once told me a great story of how he learned to be an entrepreneur. He was released from the army after World War II and an uncle of his had a business buying up army surplus junk at cheap prices. One of the things he purchased was a large container of rifle slings. Since the army didn’t want these used in weapons, they cut each of the slings in half. My father’s uncle said to him, “OK, I just bought this pile of useless half rifle slings. Your job is to invent something to do with them so we can sell them.” At that time my father lived in Brooklyn New York. He gave some thought as to what he could do with cut-up rifle slings and then went down into the New York subways to sell his "new" product. He approached the people who ran the shoe shine concessions and sold the cut-up slings as polishing straps for shoes.
The moral: give someone a problem, tell them to solve it, give them a kick in the rear and say, “go,” and innovation will result. This is where street smarts, necessity, and creative problems solving merge.