Multiple air barriers and iron webs of the synchronous reluctance motor (SynRM) are vital to achieving higher average torque and a lower ripple torque. However, it is challenging to determine the optimum multiple barriers because the optimization results are significantly affected by the initial flux path and moreover are sensitive to a penalization scheme in the topology optimization. Interestingly, in nature, the hollow circular patterns of the trabecular bone at infancy gradually adapt to the optimal (also very complicated) trabecular architecture, which provides a characteristic lightweight design. Inspired by the above observation, this study proposed a novel topology optimization for multiple-barrier SynRMs, which initially started from random hollow circles. To distinguish between iron and air, the dq-axis-dependent penalization scheme is also proposed instead of a conventional spatially constant penalization scheme. Using the adjoint variable method, the analytical sensitivity was derived to consider a nonlinear B-H curve in the topology optimization. By optimizing various SynRMs with different filtering radii, this study investigated the relationship between multiple barriers and motor performance.