Have I ever told this story before? Let's say you could somehow flag every single atom in a full grass of water. Then you take that full glass and dump the water in the ocean. Do like the Soup Nazi says, "Come back; one year!" This will give the atoms time to disperse throughout the ocean. Fill the same glass up with a scoop of water from the ocean. It is guaranteed that at least one atom of the water in the glass will be flagged from the original glass you filled up a year prior. Why is this? Well there are as many atoms in a glass of water as there are glasses of water in the ocean. Rap your mind around that one for a few minutes. That's one mole of a tale isn't it? That sort of stuff just Boyles my mind!