Write a scene in which at least three layers of action are happening simultaneously. You may come up with your own actions, or you could use this one:

A character is trying to load items on a truck parked in a loading zone (layer 1)
when a rain/wind storm blows up and trash and debris start flying (layer 2).
Meanwhile, all the people on the sidewalk start running for shelter, making things quite difficult for our truck-loader (layer 3).