Idols

A very common way to relate arcane use to its application is through the Sympathetic Law. It states that symbolic links can be used to channel energies. Practitioners who use idols do this by making figurines, dolls, or other objects that roughly takes the shape of an entity their ritual aims to affect. Idols can also be used to draw on the energies of various gods or other powerful beings called on. For instance, a crucifix used for exorcism can be considered an idol.
In order for an idol to work in an optimal way, it should have some part of the target attached to it or be a very exact portrayal. An object that the target has had close to them for a long while and emotionally connected to might be enough. Preferably, of course, all of these things are used.
A wise user of idols in their practice makes sure to have several different ways to access them when needed rather than relying on a single one. Those used to call on the power of a higher being are often made in a form that is easy to carry. A priest might wear a necklace with a holy symbol, for instance.

History

The use of idols is one of the longest traditions for arcana and provides great protection from Thorns at the cost of requiring a lot of preparation. The earliest traces of magic uses predates written language and knowledge of it mostly survives through a few remaining idols and some cave paintings. For example, it is generally accepted that the 25,000-year-old was used as an idol.

Examples of traditions
Runic symbolism
Thaumaturgy
Voodoo