The pyramids of Snefru show the development from the step pyramid to the real pyramids. In general this is considered to be a quantum leap in the field of construction engineering. The bent pyramid is said to be an experiment that went wrong.
The bent pyramid is the breakthrough:
It is the bent pyramid that served as the actual model for success in pyramid construction. The pyramid is in fact the ramp they were always looking for, but also the most efficient ramp possible.
This was the pyramid where they tried out the method of simultaneously and directly transporting the stones via the flanks for the first time. It was this that actually heralded in the great era of pyramid building.