The purpose of the animation is to highlight impotance of phase difference when oscillations are added. Two SHM's along the x-axis of differing amplitudes and frequencies are being added.Motion of the green particle and yellow particles are x1 = A1 Cos(ω1t) and x2 = A2 Cos(ω2t+δ) respectivley The red particle (when show sum check box is ticked) shows the resultant motion. The two force vectors causing the motion are also shown. How the phase difference between the two affects the resultant oscillation is shown visually. The reference circle drawn on the right, highlights the phase difference. The radius of the reference circle is not to scale.