ancient Stone Slab Arrangement . Each set of stone slabs are placed one next to the other and in layers. On top of each stone slab a hole is drilled such that the holes in stone slabs that are one on top of the other are aligned together. Before laying the stone slab on top, an iron rod is place on the hole in the bottom slab and the stone slab on top is placed such that the iron rod fits into the top slab as well. This secures two stone slabs, and their weight keeps them in place.