The vèvè constitute a complete visual system — a distinct design for each lwa, with regional and house variations — and their status is unusual. They are drawn from memory on the ground at the beginning of a ceremony, function as summonses as well as signatures, and are obliterated by the dancing within the hour. No effort is made to preserve them; the versions printed on cloth, painted on drums or sold in galleries are commercial products, and the ritual object is the temporary one on the floor. As a body of transmitted knowledge they are scripture-like: they encode which lwa is which, they must be executed correctly, and learning them is part of a priest's training. That a tradition would organise its iconography around images made to be destroyed the same day, by the feet of the people they summoned, is a striking design and is entirely consistent with a religion that keeps nothing in writing.