A polygon can be drawn from the coordinates of its corners, its vertices. When two vertices share an x-coordinate, the side between them is vertical and its length is the difference of the y-coordinates. When they share a y-coordinate, the side is horizontal and its length is the difference of the x-coordinates. From side lengths come perimeter and area, in all four quadrants. The crew tapes a coordinate grid on the garage floor and lays out the clubhouse walls with string.