It´s fascinating (or is it disappointing?) how traditional meditation phenomena can be reflected in modern neuroscience. 

One of these phenomena are the "thiglets":  shapes and forms that follow a defined sequence of appearances.  In Tibet, they were imbued with spiritual semantic. In modern neuroscience, they are attributed to activation/deactivation of brain areas in intense meditation conditions. 

Here are the five stages of the development of By-Passing visions (source: Shardza, see References)

*   Stage 1 (Increasing): Simple, unstable energy drops (`thig le`), shimmering filaments, and splashes of color begin to appear.

*   Stage 2 (Spreading): Visions become more stable, self-organizing into geometric patterns, mandalas of light, and partial deity forms.

*   Stage 3 (Flourishing): The process becomes automatic, revealing entire, complete Buddha-fields and fully-formed deities.

*   Stage 4 (Completion): The field is filled with unwavering, intricate visions of fully adorned deities and complex mandalas containing Buddha families.

*   Stage 5 (Exhaustion): All visions—lights, forms, and realms—gracefully dissolve back into the empty, aware space of the universal ground.

Instructions to develop these visions used to be secret, but today one finds them anywhere, for example here. 

It is unlikle though, that  "Buddha families" will appear to modern non-Tibetan meditators.  This is just as unlikely as the appearance of Jaguars to Ayahuasca users in the West: much of this specific content is patterned by the cultural and natural environment.  It just shows how different areas of the brain interact.