Draw a horizontal line on the bottom of the page. Add a double set of horizontal lines above it. Sketch six sets of double vertical lines perpendicular to the double horizontal lines. On the outer left- and right-hand sides, sketch slightly bent lines to connect the two sets of double vertical lines as shown.
Connect the middle two sets of double vertical lines with intersecting horizontal lines. Add two more horizontal lines to connect the tops of the remaining vertical lines. Draw a double set of horizontal lines on the rectangles as shown.