This, in turn, allows us to define precisely what a reconstruction from incomplete information is: it is a reconstruction from a number of proections which is at least one order of magnitude inferior to the theoretical minimum number which is required to make a complete reconstruction.
As we can see, the problem can be given a precise formulation, but what really counts is that it can also be given a solution. It has been demonstrated in fact that structures can indeed be reconstructed by using only 10% of the minimum number of projections (Barbieri, 1974; 1987), and an iterative algorithm which exploits memory matrices (Figure 7-6).
More precisely, a reconstruction from incomplete projections is possible if two conditions are met: (1) if the reconstruction method employs memory matrices where new information appear, and (2) if the reconstruction method employs codes, or conventions, which transfer information from the memory space to the real space.
The reconstruction of structures, in conclusion, gives us a model that translates epigenesis into a workable problem, and tells us that memories and codes are the key structures for achieving the goal of a convergent increase of complexity.

Multicellular structures

The reconstruction of individual structures can be a model for the development of individual cells, but not for multicellular systems such as embryos. In this case, a model must be capable of performing in parallel a plurality of reconstructions, while taking into account a variety of interactions between individual structures. What must be simulated, is an increase of informational content between initial and final structures, and on this point the reconstruction model is crystal clear. The difference between initial and final information, and therefore the overall increase of complexity in the system, is entirely dependent on the memories which are used in a reconstruction, because it is only in the memory space that new information appears. In the case of individual structures, a reconstruction matrix can receive new information only from its individual memory matrix (Figure 7-6), but in the case of multicellular structures there is also another option.