Here's what I'd do. Create your dropzone. On top of that create a rectangle with a red gradient. Then create a square shape and make a replicator out of it so you can have the 8-square pattern that you see in your video. Add an image mask to your red rectangle and use the replicator as the source for the rectangle. Duplicate the replicator and apply the duplicate as the image mask for the drop zone.
Then you can add a sequence replicator to the source layer for the rectangle's image mask and using the parameters adjust the opacity of some of the squares so that the drop zone below shows through.
Andy
http://www.timesavertutorials.com
