Mental activity entails the arising of a cognitive appearance of something, which is equivalent to the cognitive engagement with something. The cognitive appearance resembles a mental hologram and seemingly appears to be truly established by a self-establishing nature from its own side. There are several possible explanations for what these mental holograms are made of and how they appear with this deceptive mode of existence. Here, Dr. Berzin explores several hypotheses: the winds of karma, the four creative-energy drops and subtle particles from the Kalachakra system, devoid-forms also from this system, energy-winds from the Guhyasamaja system and reflexive appearances of rigpa (pure awareness) from the dzogchen system.