This is a continuation of my Specifics of magical symbols and casting series of questions.
Air-Drawn magic in this world would be invoked in a similar process as emotions, the brain of beings in this universe, much like ours with fight or flight, recognizes when the being is attempting to channel magic. This can be used in many ways, channeled to sticks, stones, weapons, and even more abstract things like speech, thoughts. However, for this scenario, as a person sticks out their finger (or other appendage), while channeling magic, they can draw symbols in the air, which the "Magic Layer" that permeates all things automatically interprets as something, or nothing.
However, there are in-betweens. What makes air-drawn symbols difficult to master?
Could it be something that could be combined like a written language - would there be cursive or other variations in writing?
The symbol being drawn can be perceived, not necessarily physically seen. As every person and being is unique, the DNA mixed into the body's magic inductor makes it function more similar to how humans, ants, other creatures in our world can smell or otherwise "sense" pheromones. That does mean, that every creature can see these motions and the apparent "effect" in the physical realm, however this could be masked, much like pheromones in the real world.
It is also a very short-lived effect. Say, like a trail behind a finger as it traces, it is only visible for at most a second to the untrained senses.
This mechanism is solely an evolutionary trait that allows users to see what they're doing, and doesn't affect their magic abilities, unless their ability to sense these kinds of traces are hindered.