Thank you for the kind comments.
immersionfx: I thought that you are talking about objects like boxes, barrels and so on for a moment. Stacking entities can be done pretty easy using a starter function that includes a while loop. You can save the position of the entity (maybe the angles, the current frame, and so on) every x frames, and when the "distance" between player's current position and the virtual position of the entity is smaller than some value, you recreate the entity in the level. I might cover that in a future Aum article.