So, I was at home fooling around and a question just came to me...
Imagine that you are at the beach, and you're there all happy and building sand castles and etc.
But then, you decide to do a sandpile.
Ok, you put a lot of sand together and there you go, u already have ur sandpile. But imagine that you took out just ONE grain. It still a sandpile, right? Ok, then you took out another one. It still a sandpile. And then you go, taking out grain by grain.
So, the question is: How many sand grains make a sandpile? Because if you just remove one grain, it still a sandpile, if you just remove two, it still a sandpile and then it goes.. But when there's only one grain left, is it a sandpile? If not, when it stop being a sandpile?