For an AR(2) time series, the triangular region below is the
region for the parameters that ensures the time series is stationary. If the
parameters lie in the region below the parabola the autocorrelation function is
is a **damped cosine wave.** You can control the parameters by moving the
red point around in the triangle. If you want to see a realization of this
check yes and press the **generate a realization **button. The maximum value
for n is 600.