The rubbersheet economy (as a dialogue):<p>1. Prices move according to the law of supply and demand.<p>2. Right: why do they move though?<p>1. Simple: every hour the central government determines the current supply and demand for all goods, and computes the right price.<p>It looks like a market economy, the prices move in the right direction (the balls are &quot;attracted&quot; to each other), but the explanation is a planned economy (the effect of Earth gravity).