The Ghost Universe consists of several Ghost Worlds, each
interconnected by Datastreams (Echo-Paths).
Travelling the Datastreams is a specialized skill: by channeling the
Ghost Field, some adepts can open temporary Gates to the Paths.
Using the Major Arcana (e.g. Amber Trumps) is one of the many possible
ways of Pathworking!
Other Traditions use: Tattva Symbols, Hermetic Seals, Bagua, etc.
A Grip who is specialized in Listening at Echoes, has the skill to
detect functional Paths.
Every method has its own risks….