This is a kind of stacked balance *with* what I call Programmed Collapse. This is where the rocks are balanced in such a way that they all disappear back into the water or elements upon collapse, using gravity to erase the footprint. This almost always depends on counterbalancing. the lowest rock (or first moveable rock) either on point, or at some kind of downward angle, where the weight of the top rock is required to keep the bottom in balance.
In this example, based on how the tension of the thread felt, the whole will most likely begin collapsing at the narrow connection under the spotted rock, which will unbalance the lowest one. Not a soul would have a clue of my presence.