The neutron is the first “micro-donut”—a saturated T² configuration whose bi-rotating character traces a pseudo-dense path across the toroidal fiber. This chapter develops the micro-donut picture: bi-rotation at speed c yields E = mc² kinematically, pseudo-dense coverage explains the neutron’s featureless appearance, and the saturation principle establishes stability. The ternary structure of hadrons—baryons as three-fold and mesons as two-fold T² composites—then follows from the three-fold covering structure of the C-sector . The donut ladder extends this architecture from 10^{-15} m to 10¹⁰ m.