The magic of shapes is called sympanometry. Shapes combined in certain patterns become sympanetic, creating forces by channelling natural energies. While most people think of sympanometry as magic, more than a few of its practitioners maintain it is a science.
On Earth, for example, had our ancestors got a bit more hands on with geometry and actually built some of the geometric figures they drew, they probably would have stumbled across the special relationships that exist in the space-time continuum between certain shapes.
On the other hand, maybe they did find out more that we know. Some of the more controlling – or possibly paranoid – geometric dabblers kept their discoveries secret. Secret societies sprang up to guard the little that had been discovered and did a fairly good job of ensuring that not much in the way of physical geometry made it into the public gaze.
In spite of this the occasional dabbler in arcane matters would notice certain things, like pentagrams having properties that made them useful in magic rituals, but didn’t make the connection that it was the relationship between the position of the triangles formed by the pentagram’s points and the pentagon in its centre that caused the effect, not the outside shape of the pentagram itself.
Even though humans never developed sympanometry they still had an instinctive feel for shapes. People developed rules that defined the shapes of objects in architecture, art and even tax forms because certain ratios of length to breadth, height to width and so on just felt right. Golden rectangles, The Flower of Life, Metatron’s Cube, Celtic Knots and so on were the first stumbling steps towards sympanometry.
Beings from other worlds have developed sympanometry to a far greater degree and brought that knowledge with them when they came to Hollow.
Sorcerers tend to be loners. Not always by choice but because of what they might do if, say, someone spilled their drink over them while having a spirited discussion in the pub. Who would want to be friends with someone who might turn you into a small slimy creature at the slightest provocation? Seeing as sorcerers tend to deal in the dark side of magic they are often a little less than charitable.
If sorcerers aren’t often to be found at parties, necromancers are even less likely to find themselves invited to social events. Their practice of conjuring the dead tends to leave their diaries a little on the light side. There aren’t very many necromancers to be found in Hollow which is something of a relief.
Technically, magic is not any particular colour. But in the sense that good magic is said to be white and bad magic is said to be black, the colour of most magicians’ magic is a fairly dark shade of grey. It’s not that magicians start out as bad people, it’s just that it’s far too tempting to use magic to get back at people who annoy you.
There are some who combine several of the magical disciplines. The kynbar are adept at combining ordinary magic with sympanometry for example. Scientists often incorporate sympanometry in their research but are rather less than enthusiastic about other types of magic.