Directions
With using a mask you will create a hidden picture.
- Open a new document and import a picture to the Library, then to the Stage, on a layer by itself. Rename that layer “hidden”.
 - Then on a new layer called “mask” make a unique looking symbol that will become a mask.
 - Make that symbol a movie-clip. Inside the movie-clip add some type of movement, using at least 2 motion tweens with a new symbol.
 - Mask the “mask” layer so you can see the hidden layer.
 - Add ActionScript to the symbol so the mouse stays with the symbol.
 - Lastly, add a new layer called “cover”. Add a picture or text that will be covering the hidden layer.
 
Example:
