Four-Dimensional Closed-Loop Logic: Structural Dynamics of the 45° Inclined Conical Growing Universe

This paper proposes four-dimensional closed-loop logic, a structural-dynamic system based on the 45° inclined four-dimensional conical growing universe. It follows a complete geometric cycle and is valid only within the 45° conical universe, which can be analyzed by the Pythagorean closed frustum model. The system realizes cosmic stability, symmetry, and order, and provides a self-consistent framework for understanding universal structural laws.