The AlienBot should leave a Thing in each intersection of the square region. Use stepwise refinement: Write a method called oneRow that makes the AlienBot travel along a single row from left to right, leaving a Thing in each intersection, and then also makes the AlienBot move back to the beginning of the next row, again facing east. The oneRow method will need to take an input of type int indicating how long a row is. Now your makeSquare method can be very simple, since it only needs to call oneRow the appropriate number of times.