This experiment is an exercise in chapter 8's Activity #2: Boe-Bot Shadow Vehicle.
The circuit of this experiment is exactly the same as the avoid table edge experiment, only the programming codes is different. Boe Bot will follow
the white sheet to move left or right, it will also move back to avoid colliding with the white sheet when it is close.
It is exactly the same as the book except that I modify the program to light up the two red LEDs according to which way the Boe Bot is turning.
