That is what I was thinking. <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />
Another way to look at it is a leaky bucket. As long as you are in the hexagon where the Water tap is, the bucket fills up. The more experienced you are, the bigger the bucket is and the quicker you can fill it. You can use the Water as you stand there and it will keep on replenishing.
Once you leave the tap, the bucket starts leaking. It leaks quickly at first because of the water pressure, but slows down as it becomes less full. You can still use the Water, but it isn't replenishing because there is no Water tap. With experience, you can plug the hole slightly, reducing the rate of leakage.
And then you also have a balloon for Air, a sack for Earth (from the Earth Tap), and a keg of gunpowder for Fire. <img src="/ubbthreads/images/graemlins/delight.gif" alt="" />
