What is one geometrical fact explained in the lecture that reflects the mathematical technique da vinci used in the last supper

He uses the coffers of the ceiling to place Jesus in the mathematical center, and to create an illusion that extends the room beyond what is visible.

Generally spontaneous human combustion is something that still bewilders some, human combustion happens very rarely and doesn't affect the surrounding areas, so unless you want to set your self on fire, human combustion will remain spontaneous and very rare.