I used 3/8" steel square rod cut in lengths of 4". These sectioned are not attached to each other in any traditional way. With a magnet at the base, this structure is able to balance with far more stability than other non-ferromagnetic materials. The astute among my audience may have noticed that the loads on each side are not balanced,...

This is one of my rock structures, there is no glue or adhesive, just gravity and friction.