Add a bit of subtle action. Using the same file you created in the last tip, here's how.
In After Effects go to File>Import>Footage and select the rectangle file.
Drag the file to the New Composition button in the Project Window.
Select the layer, and press S to open the scale property.
Make two keyframes: one for 200 percent and a few seconds later for 100 percent.
Duplicate the layer and apply a multiply mode to the top layer.
Select the top layer. Press U to show the Scale keyframes.
Select the keyframes and choose Animation>Keyframe Assistant>Time Reverse Keyframes.
Reduce the opacity of the top layer as desired.
Do a RAM Preview by pressing 0 on the numeric keypad.