Those Egyptians were smart. That's a cool trick....and yes it is very hard to "eyeball" a pole on a steep hillside. It looks plumb until ya get a plumb bob and then you see that you need about 5 pole tops over. Lol
Pretty sure if I pull that trick on my crew, I'd get some pretty funny looks......screw it, I'll just tell boss that's how the ancient Egyptians did it. Jk.