The celebration of materialism (on the rotating iron balls):
Due to the sinking in the locations of welding the armature of the walls and coverings there is increased tension. It grows, then there is a "breakdown" - a small shift of the contacting materials - the very first louder sound, similar to the fall of an object. Then begins the redistribution of loads on the armor bar with a differing wave - it seems like something is rolling. Then the forces acting on the bar are balanced. The sound disappears. The walls and covers of these bars are full. People have heard these sounds for years.

one