Hundertwasser's architectural designs were characterized by their irregular shapes and an abundance of greenery. He believed that architecture should be in harmony with nature, and often incorporated elements such as trees and plants into his designs. One of his most famous projects, the Hundertwasserhaus in Vienna, is a prime example of this philosophy in action. The building features a rooftop garden, irregularly shaped windows, and a colorful façade decorated with ceramic tiles and murals.
Hundertwasser also believed that people should have a say in the design of their living spaces, and often involved the future inhabitants in the planning and design process of his buildings. This approach to architecture is known as "participatory design" and it aimed to create a sense of community and ownership among the inhabitants.
Another important aspect of Hundertwasser's philosophy was his rejection of straight lines and right angles, which he referred to as "the straightjacket of the human spirit." Instead, he advocated for the use of curves and uneven shapes, which he believed were more in line with the natural world.