[airspirit]

The only problem with this is that it will introduce stagnant areas behind the outlet baffles. But it illustrates how the flow is manipulated by the suction from the outlets.

Oh, and another way to illustrate this: those lawn sprinklers that spin around use this same principle to cause them to spin. Since the BLOCK isn't going to spin, the water will. You can't just neutralize forces in any equation.

Edit: nevermind the illustration. It wouldn't work because of the baffles. They would impede the circular flow. You're sure to have someone with a spinning lawn sprinkler living around you ... just look at the part that makes it spin. It looks remarkably like this block design (not the below illustration, but the above ones).