The thinner section in the middle is the 1, and the two outside sections scaled at 1.618.
“The golden ratio” might look similar to the Rule of Thirds, but it has a ratio of 1 to 1.618. Using this ratio, we can draw a similar grid to the one we had in the rule of thirds, but the center section is smaller than its two outside sections. The thinner section in the middle is the 1, and the two outside sections scaled at 1.618.