How to make walls on pk heads 3d engine

hey pk head or anyone that knows how to do it I would like to know if there is any way to make a wall in your 3d engine this would be pretty helpful since I’m making a 3d game

Its unfinished also I don’t recommend wick to mak a 3d game engine its meant to be 2D

yeah ik but I can’t make 3d games because I have a school computer