Choose a value for the tune Q, and for the sextupole strength b2, then enter the number of iterations. Hit return to make the number appear on the button that intially says "0 more", and then click the mouse in the window where you would like to launch a test particle. You may repeat this step several times! The following equations are used to generate the motion:
until done {
Rotate (x,x') by 2*pi*Q
x' = x' - b2*x2
}
For example, you might want to try Q = 0.320, b2 = 1.0, and 1,000 iterations.