It cannot occur in two-dimensional phase spaces but in three-dimensional flows such as the Lorenz equations used in an early weather simulation it can appear.  
Although a positive Lyapunov exponent is not required for this behavior, it is typical.  It cannot occur in two-dimensional phase spaces but in three-dimensional flows such as the Lorenz equations used in an early weather simulation it can appear.  For ten points, what term describes apparently random behavior in a deterministic system caused by sensitivity to initial conditions.
Although a positive Lyapunov exponent is not required for this behavior, it is typical.  
chaos