((Subject to Massive Alterations))
Any mage with sufficient talent and trainning is capable of executing some of the most powerful and complex spells known to mortals by simply muttering a few incantations, scribbling a few runes and/or simply directing their will-power towards a certain goal. However, very few actually realise the complexity and the true nature of what these actions reflect. To most mages, the apearence of a small pastry on their hand is a direct consequence of a mere drivle of words. The reality, is that these words merely aid our minds to rearrange the Arcane Weave aound the hand, thus causing the organised formation of that pastry as a side-effect.
In it's natural state, Arcane energy tends towards forming hierarchical lines and shapes that are generally recognised as runes. The greatest of these lines are known as ley lines, and criss-cross the surface of our world, like a huge tapestry. Between these thousands of weaker lines criss cross in complex paterns, and between these even smaller patterns of arcane fill the spaces. It is this huge patern that the arcane naturally produces that we call the Weave. Any spell of an arcane nature that is cast is no more than the rearranging of these same lines, a process which causes the desired side-effects.
The individual rearranging of each of these lines is a process of extreme complexity, so it is fortunate that it is generally unecessary.
One of the simplest ways of rearranging the Weave is through the use of Runes. When a rune is written and imbued with arcane energy, it naturally rearranges the weave around it, causing the effect associated with the rune.
The most common technique involves the channeling of arcane energy through the caster's body. The very soul of the caster, often aided through incantations, issues instructions, and consequentially the arcane that arrives at the focal point(s) forms the desired runics paterns. It is well known that unlike the direct use of runes, this process of manipulation can cause the soul and body of the caster to slowly become imbued with the arcane, thus causing alterations.
It is also thanks to the Weave that magi are capable of feeling the use of arcane magic in their proximity. The rearranging of a small section of the weave causes ramifications within a radius that can extend for miles, and anyone attuned to the weave can sense this.
All seven schools of arcane and elemental magic (I refer to arcane elementalism, not spiritual tribal practices), can be analysed and studied in reference to their effects on the Weave. An understanding of this allows magi to discover/create entierly new spells, but this is a highly complex process that only a handful of academics are capable of.