According to official timeline and amount of stones they should place one in every few hours. You realize that you have to be absolutely perfect with the stones, as if you make little mistake near the base then the tip is not going to be in the center. But it’s so precisely in the center it would be a amazing achievement even today.
Dimensions and proportions contain speed of light, size of Earth etc. It’s aligned with true north being just fraction of a degree off, something we need satellite data to do. And so on..
And there are those rocks in the desert we could not transport today. But everyone can believe only what they want to believe. I want to believe we are not very advanced yet comparing to our ancestors. It gives me hope.