Late Old Kingdom (2150-2040 BC).
False doors, a sort of funerary stela, placed on the western wall of the superstructure tomb temple.
All rituals, such as spell and offerings from the priests and the family of the deceased, were performed in front of the false door. It was believed that the Ka (spirit - life force of the deceased) rose from the secret subterranean tomb chambers to the world, through a horizontal slit on the false door and by taking the offerings (food, flowers and aromatic essential oils) continued to live in eternity.
So according to the religious and magical beliefs of ancient Egyptians, the false door was the point of contact - some sort of hole- through which the world of the dead communicated with the living.