This project aims to design a pavilion in 'Seoul-Forest,' a forest of outstanding conservation value in downtown Seoul, South Korea. The project starts with the simplest form, the 'triangle,' and explores the process of aggregating multiple triangles. Through this process, we were able to discover a way to manipulate the combination of triangles to create a saddle shape. This allowed us to produce a structure whose shadow resembles that cast by the forest itself. Although the method is artificial and logical, the result's similarity to something created by nature was a particularly intriguing point for us as architects. The pavilion is designed to serve as an extension of the forest, allowing people to rest in its beautiful shadow, disconnected from the urban environment.