Its a symbol of power and the way the pharaohs get into the afterlife after dying
Explanation:
Pyramids are supposed to be not only the resting place of the pharaohs but also a path to the afterlife. The various paintings and pictures in the pyramids are there so the pharaoh can remember his/her past life and who he/she used to be. Also the various rooms are so the spirits including the pharaoh can have good fortune in the afterlife. I may be incorrect but that is the best i can do.
