There seemed to be no motion. An observer may have assumed that the ball was going to stay in that position. However, once slightly disturbed one way or the other, the ball would move quickly away from this point of balance. That quick move is a chaotic move. Markets exhibit this chaotic behavior.
Markets always have two solutions.
The buyers represent a force driving prices higher. The sellers represent a force driving prices lower. When the buyers and the sellers balance, prices will form a congestion zone. When that congestion zone ends, the balance has been tipped in favor of the buyers or the sellers. At that point a chaotic move occurs.