With loop animation, you only need to draw a short background and then repeat it again and again (loop background). Without this technique, you have to draw a mile long background.

The finished animation is shown as below:

Toon Boom Tutorial Movie

Toon Boom Tutorial Tips:

To do the flash animation repeat seamless, you have to match the position of the first frame with the position of the last frame. Remember that the background is keep on moving, therefore the position of the last frame should be a bit ahead of the first frame.

Position of Building at First Frame

Position of Building at Last Frame