Animated LED for Bike Turning Signal

Using circuit below, we can animate the bike turning signal using LED. The bike turning signal will blink from the right side (D1) to the left side (D5) in a bar style.
Animated LED for Bike Turning Signal

To build a complete left and right turning signal, you must build two units of this circuit, and arrange the LEDs so the other circuit will blink to the other side direction.