Lawrence Guth continues MIT's 18.156 Projection Theory course with the second half of a two-part treatment of sharp projection theorems. The lecture centers on the Orponen-Shmerkin proof of a sharp projection theorem for sets with self-similar spacing, extending the argument to the Ahlfors-David regular case. Guth works through the technical machinery needed to push the earlier bounds to sharpness, building on results developed in the prior session. As lecture 23 in an 81-minute graduate-level sequence, it assumes familiarity with Fourier analytic and combinatorial methods in geometric measure theory, and it sits within a broader course tracing the development of projection theorems from Marstrand through recent sharp results. The board work is dense and the pace is that of a research-level seminar rather than an introductory course.