The Egyptians probably constructed the pyramids via a system of ramps, which would have allowed them to drag the enormous granite blocks on sleds. Most existing theories about the pyramids include the construction of enormous ramps. Any single external ramp, in order to stay at the right gradient, would have to be more than a mile long. Alternatively, a spiraling ramp would be structurally unstable. By using an internal ramp incorporated into the structure of the pyramid, these problems could be avoided. The internal ramp could easily stay at the required 7-degree gradient, and there would be no problems dealing with the increasing narrowness of the building.
If the pyramids were built in a spiral, then the blocks themselves would act as a ramp without the need to construct a complicated external scaffolding. One large external ramp would have been used to make the base of the pyramid, after which the Pyramid would have been built in a spiral. Notches in the internal ramp could be used in combination with cranes to negotiate sharp corners. 
The inventor of the internal ramp theory, Jean-Pierre Houdin used 3D-modelling software from Dassault Systèmes, which is typically used by architects and engineers, to test his theory. The software appeared to confirm this method would allow ancient humans to successfully build a large pyramid.
The internal ramp theory bypasses all the problems with the external ramp models, such as structural soundness, space around the pyramid, and the construction of the pyramid’s corners. The model was successfully tested with 3D-modelling software.