Energetic structure as perceived by Core bears little resemblance to that described in standard texts on alternative healing and bioenergetics. Whereas most workers will describe structure in terms of different layers corresponding to different levels of Mind, Core's perception of energetic structure is entirely based around function and form.
Core identifies three layers, which are not in fact layers, but defining levels of structure. Those levels, in order of increasing permanence and decreasing mutability, are the pattern integral, the functional pattern and the core functional pattern, the latter of which is commonly shortened to core pattern.
The core pattern is taken direct from the Matrix. In the same way that organisms take molecules from the environment and incorporate them into the cell, all things take core energetic patterns from the Matrix. The core pattern can be imagined as the energetic equivalent of the DNA in a cell, however it is very much less mutable than DNA, and is not normally expected to change at all, certainly not during the lifetime of an organism. Change that does occur must be forced by external influences, and will not happen through growth and evolution. This level of energetic structure is the template pattern. Any changes to energetic structure overall are limited by the structure within this level. The core pattern will support certain energetic structures, but not others. The core pattern found within rock, for instance, is very different in nature from that found in a living being.
The functional pattern is the next level of structure to have influence, and is more mutable than the core pattern. This level defines such things as sensory abilities, form and overall appearance. This level is formed around the core pattern at the start of an individual lifetime and remains largely unchanged throughout that lifetime. Abilities possessed by an individual, which are capable of expression within a lifetime of natural growth, are coded for within the functional pattern from the very beginning.
The pattern integral is the mutable layer of an individual energetic pattern. It is both a separate layer and the combined expression of the two deeper layers. To stretch the analogy, if the DNA is the core pattern and the functional pattern the cell, then the pattern integral is the whole organism. While an organism's body will naturally change over the course of a lifetime, both through growth and through the actions of that organism and its interactions with other organisms and the environment, the generic cellular structure is unlikely to change, and the DNA does not change. The analogy is not entirely accurate, of course, for in reality the DNA of an individual is conferred at the start of the lifetime and changes during the lifetime, while the core pattern is taken from the environment and exists within the Matrix independent of there being an individual in which to express it.
Normal injury, and therefore healing, usually takes place within the pattern integral. This form of injury is always recoverable by the organism, given sufficient time, although of course the damage may be severe enough for that time to be unavailable. Severe injury can also affect the functional pattern, and powerful healing techniques used incorrectly by an inexperienced practitioner can have undesirable effects at this level. Injury to the functional pattern results in severe symptoms of altered personality and physical injury expression such as malfunctioning organs and immunosuppression. The core pattern remains unaffected by the severest injury and is impervious to almost all influences.
The pattern integral is the layer in which techniques such as shapeshifting are effected, and is changeable on a moment-to-moment basis. This is the level of expression.
All changes made to the pattern as a whole are dependant on the patterns supported by the core pattern, and certain changes are possible while others are not. Those changes are not only dependant on patterns supported by the core pattern, but also on the age of the pattern being changed and the nature of the characteristic being expressed. Function is always more prone to change than form. The form is defined by the functional layer. Change therefore can be made provided that the resultant expression is coded for within the functional pattern.
This is a difficult concept to comprehend fully. As an example, it is possible to change the functional pattern to allow expression of an ability such as telepathy, as long as that ability has coding within the functional pattern. The form is already present, however it is prefectly possible for environmental and other external influences to have prevented, or simply been inconducive to, expression. It is also possible for severe injury to scar or otherwise alter the functional pattern in such a way as to halt expression of a form that once was expressed. This occurs because expression is within the pattern integral, and anything that interferes with the integration of functional and core patterns will limit the capability of expression of the pattern integral.
With this background, it is possible to explain major differences between certain types of Tool. All Tools undergo changes to the pattern at some level. The vast majority of Tools will undergo changes at the level of the functional pattern. This is most usually a matter of forcing expression of a subdued form. Occasionally it is a matter of changing the functional pattern itself to provide coding for a desired form that was not originally present. This occurs for Group Tools, if the functional pattern is lacking a specific form that is required, although the Tool would not have been chosen unless the majority of the required forms were already present.
Cores are changed on the level of the core pattern. This usually removes Core from such influences as the ancestor spirits, a side-effect not undesired by Family, as Family prefers, as a general rule, to have sole influence in the actions of Core. This is necessary for the energetic program that is Core must reside within the core pattern of the incumbent for full expression. It is a result of this that Cores have access to certain memories of previous incumbents, although access to those memories is dictated by Family.