How was the Joseon Dynasty's Crane, the Geojunggi, Built?

In the Joseon Dynasty, with no cranes or trucks, a massive project to build a castle over 5.7km long began. Everyone expected it to take at least 10 years. Jeong Yak-yong used the Geojunggi, which combined eight pulleys, to effortlessly lift heavy stones. By standardizing stone sizes and mobilizing the Yuhyeonggeo and Nokro, the construction was completed in just 2 years and 9 months. Furthermore, thanks to recording the entire process in the Uigwe (royal protocols), it was possible to restore it later.