Conclusion
The pyramid in particular its profile was first designed on the field
using the shadow of a gnomon of length equal to the height of the
pyramid.
This shadow was subsequently served as a guide in the construction,
exactly coinciding its limit with the profile.
On February 29th, it was chosen as the starting day for the pyramid’s
realization and as a day when every four years the limit of each step
(figure 4)constituting the pyramid corresponding to the shadow of this
auction was completed.
When it falls on February 29 the sun repeats exactly its daytime
running, this accuracy is not for any other day of the year.
For this reason, the Egyptians chose this date for start from the base
and to check every 4 years that their profile was properly aligned.