ck the Rectangle Tool (M) and focus on your Toolbar. Remove the color from the stroke then select the fill and set its color at R=255 G=222 B=23. Move to your Artboard and simply create a 10 x 40px rectangle, the Snap to Grid should ease your work. Set the fill color at R=162 G=179 B=189, create a 10 x 15px rectangle and place it as shown in the second image then set the fill color at R=225 G=176 B=169, create another 10 x 15px rectangle and place it as shown in the second image. Focus on the smaller rectangles and pick the Direct Selection Tool (A). Select the four anchor points highlighted in the second image and simple drag them 5px down. Again, the Snap to Grid will ease your work. Reselect that yellow rectangle and simply remove the color from the fill. Select all three shapes and simply drag them inside the Swatches panel (Window > Swatches) to save them as a pattern. Once you have your pattern you can remove those shape from your Artboard.