And the semi-reticular structure explained the overlaps between the different elements of the city. And those overlaps must be the right overlaps, as Alexander pointed out in his theory. However, Alexander did not give a clear idea of ​​how we can design a city with a semi-lattice structure. But analyzing the theories of others can help us understand how a city can develop into a natural city like Manhattan. In the case of Manhattan, we have concluded three methods to build a natural city. The first is the mix of functions, not only Salingaros but also Jane Jacob had underlined this type of thinking. Everyone thinks that a city should have multiple functions to satisfy all kinds of people. The second reason why Manhattan can be a natural city is due to the development of the city over a long period and on different scales. Brasilia took only five years to build, but Manhattan took more than 300 years to develop. And finally, Salingaros explained that small-scale urban projects are also the essential reason. These three reasons can be useful references for learning and engaging in the development of a natural rather than artificial city