Help !! Moving Blobs

This is a java programming...

The JPanel contains an array of moving blobs. As soon as the UP arrow key in pressed, each blob, defined in the Blob class, moves from the ventre of the JPanel to the left or to the right until it reaches the edge of the game area.

Once the blob reaches the outside of the game area, it becomes invisible.

The blobs can be stopped/started by pressing the UP arrow key.

Thanks a lot !!