In addition to button symbols, there is a second type of symbol called a movie clip symbol. These are like Flash movies within Flash movies with their own layers and timelines. They are independent of the main Timeline, for example, they could be triggered by a user interaction like clicking on a button.

Movie clip symbols can be thought of as rebellious symbols that refuse to conform to the rules of the Timeline they are placed in.

We will now look at using movie clip symbols to create a button that animates when you hold the mouse over it.