I recollect when as a kid I played with other kids on a tilting board, differently called a "see-saw" or "seesaw." Pushing with our feet, we would on the other hand go here and there. Simple enough to do when we were both near a similar weight. This was the place we taken in the rule of the parity scale. When one end goes down, alternate goes up. furthermore, it's the heavier end that goes down. That is how it was on the see-saw. With a normal first grader and a fifth grader, the more youthful, lighter tyke sat at the tip of his or her end, and the more seasoned one sat nearer to the center. Or on the other hand, to make it fun, at least two more youthful kids would sit toward one side to adjust a more established kid on the other. The message was clear: the bigger weight pushed up the lighter weight. A similar guideline is grinding away in a few sleeping cushions. The weight help of free-stream waterbeds relies upon differential uprooting. Heavier and bi...