To make an obelisk, first carve the whole obelisk carefully in one piece from the solid granite, laying horizontally. Separate it from the bedrock, and drill a series of small holes around it at convenient intervals. Force wedges of dry wood into the holes, then pour on water so that the wood expands and cracks the obelisk into handy sections for transport. Float the sections to their destination on rafts and reassemble it vertically in the desired place (the sections should fit perfectly where it was cracked, even though the cracks are neither straight nor level). Finally carve it as desired.
We know all this because Queen Hatshepsut commissioned the largest-ever obelisk to be made at Aswan, 41 metres tall, but unfortunately (and probably fatally for the stonemason involved) someone cracked it when it was half-finished so she cancelled the entire project. The obelisk lays to this day in a half-finished state at the quarry..
At the foot of the quarry is the loading basin of what must be one of the worlds oldest navigable commercial canals, which connected the quarry with the nearby River Nile from approx 1500 BC until its final abandonment in 1962 AD