A Voodoo cosmogram acts as a "beacon" for a type of spirit when used during their rituals.
it seems that in the course of these ceremonies ....the reproduction of the astral forces represented by the vévé obliges the spirit to descend to earth.
These cruciforms, which are common in Vodou sacred arts, borrow their outward form from Catholicism, or from something with it's roots in a far older tradition and their deep meaning from the cosmic symbol called 'Four Moments of the Sun'....just like the "crista" which if you remember has been described as ' the sun on it's horizon'.
The basic form of this cosmogram is a simple cross with one line representing the boundary between the living world and that of the dead, and the other representing the path of power from below to above, as well as the vertical path across the boundary.People who use these objects control the spirits of the cosmos connecting the living with the powers of the dead. We have Legba the god of the crossroads; he who opens the road to the spirit world. No Loa/spirit of the dead, is allowed to enter into the worshippers unless he has Legba's permission. This is because he holds the key to the gate separating the humans' world and the world of the gods.
....he is the master linguist, the trickster, warrior, and the personal messenger of destiny. He is the intermediary between the Loa and humanity. He stands at a spiritual crossroads and gives (or denies) permission to speak with the spirits. He is always the first and last spirit invoked in any ceremony because his permission is needed for any communication between mortals and the spirit of the dead - he opens and closes the doorway. .....the god of the crossroads.
....cobbled together from some notes but you get the point i'm trying to make.
Does La Sanch have a chapter in Port-au-Prince?
Are you sure you're not perhaps confusing Vaudou