Inventions: some change the world, others are just curiosities. Inventions are not like discoveries, in which a person might have an apple fall on their head and uncover a fundamental truth about gravity. They are a more finicky and complex thing. Our favorite tools, gadgets and implements tend not to result from some epiphany where a man sitting in a bath or a woman going for a run suddenly realizes what's been missing this whole time. Inventions evolve from an idea that springs from a need: "What if we could do this?" or, "I wish that were different."
Combine this impulse with a smart mind and the leisure time to work up a prototype, then add the will to fail a whole lot of times, succeed once, be laughed out of a hundred investor meetings and presentations, fail a bunch more, succeed again, get a little seed money, prove your concept, secure your patent, and not give up along the way... and maybe, just maybe, you have an invention. Suddenly everyone will rally around to cheer on the genius mind out of which this wonderful new gizmo exploded fully formed, overnight.
It's a short hop from there to a great fortune and a device so recognizable and significant that you can tell what it is from a single photo. So let's see which of history's great inventions made it all the way to that stage in your mind - and which did not!