The Explorer in the Cave
by Roberto
Imagine, if you will, you are an explorer. Curious. Fascinated, enchanted even, by the natural world, in all its richness and beauty. Now, you find yourself exploring a wondrous cave whose walls are stunning; studded with shining crystals. Crystals you begin to collect for their sheer beauty. No doubt, you also appreciate their enormous value. Selling them will bring unimaginable riches.

The Explorer in the Cave. Source
As you pluck each gem you notice drops of water seeping out from the tiny orifices left behind. But there's something odd going on. "That's interesting," you think out loud, "every time I pull out one little rock from the wall, twice as much water comes out." You go on picking, oblivious to the tiny puddle slowly forming at your feet. Yet, with every gem you collect, the volume of water oozing out from the cave's huge wall doubles.
You begin to realize your time to collect gems is getting short, so you frantically increase the speed at which you collect. At first you took your time, carefully inspecting each one, appreciating their individual beauty. But after extracting so many you've gotten much faster; you're now plucking out one gem per second, no longer even glancing at them. The water reaches your waist, yet you keep at it. "There's still plenty of time before I have to leave. The cave is huge and there still so much to pick from these leaky walls. I'll be sure to exit with plenty of time; it'll only take me a few minutes to find my way out."
You continue to pick at this now frenzied pace until the cave is half full, your feet barely touch the bottom. It is time to head out. Reaching for one more shiny, beautiful, priceless bit of rock you turn towards the exit.
...
But in one more second, the cave is full.
...
Why? It's exponential growth (more next week).
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