In order to solve this problem, the robot must have the following physical properties. It must be able to reliably move between squares within the 4 x 4 grid, and be able to turn in place to face each of the four squares adjacent to it. The easiest way to accomplish this, is with two motors connected to two different wheels, and a spherical wheel in the back to stabilize the robot. This makes it possible for the robot to turn in place simply by running the motors at the same speed, but in opposite directions.

Each square on the grid is black, and surrounded by thick white lines. This makes it possible for the robot to detect the intersection of two squares through the use of light sensors. With two light sensors, the robot can move forward until one of them detects the white line, then move only one of the motors until the other sensor detects the line. This ensures that the robot will be straight, and allows it to then simply move forward for a given distance until it reaches the middle of the next square.