This lecture covers advanced mechanisms design, focusing on kinematic analysis and geometric modeling. The instructor discusses the definitions of kinematics, including mobilities, kinematic chains, and loops. The Gruebler formula is introduced to calculate degrees of freedom (DOF) in mechanisms, with examples illustrating both 2D and 3D analyses. The importance of avoiding overconstraints and internal DOFs is emphasized, as well as the concept of isostaticity. The lecture also explores geometric modeling techniques, including direct and inverse models, and their applications in calculating motion ranges and optimizing systems. The instructor highlights the significance of calibration and error modeling in flexible mechanisms. Finally, the lecture addresses flexure optimization, presenting methods for modeling and validating designs through finite element analysis (FEM) and analytical approaches. The discussion concludes with material aspects related to fatigue in flexible mechanisms, emphasizing the importance of selecting appropriate materials for optimal performance.