Though she isn't a household name these days, silent film star Lawrence appeared in almost 250 films and even today we all owe her an enormous debt — not for her films, but for her inventions. Thanks to her acting career, she was able to buy a car, a rarity at the time. Lawrence loved driving and, in 1914, created a mechanical signaling arm that raised or lowered a flag on a car's rear bumper to let other drivers know which way a car was turning. She also invented a brake sign that popped up when the motorist pressed the brakes. Today all vehicles feature turn signals and as well as brake lights, but Lawrence never bothered to get her inventions patented — and thus never made a cent or received recognition for her creation. Her mother did patent her own invention in 1917 — the first electrical windshield wipers — but didn't see a profit from that, either.
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