The arithmetic of the Ifa corpus is worth setting out plainly, because it is the part a reference page can state exactly. Each cast marks four positions twice over, producing two columns of four. Four binary positions give sixteen possible columns. Two independent columns give sixteen times sixteen, or two hundred fifty six figures in total. Sixteen of those have matching columns and are the principal odu, named with Meji; the remaining two hundred forty have unlike columns and take compound names built from their two halves. Iwori Meji is the third of the sixteen in the sequence as commonly published.
The reason the sixteen are singled out for teaching is not that they are more powerful but that they are the components. Learn the sixteen and their order, and every one of the two hundred fifty six can be named and located. Fail to learn them and the corpus has no index.
This is also why the sixteen are what a public reference can usefully describe. They are structure. The two hundred fifty six carry the content, and the content is the part held within initiatory transmission.
The same sixteen-figure architecture appears in several West African and Malagasy divination systems and in North African geomancy, and how those systems are related to one another is a live scholarly question rather than a settled one.
Iwori Meji's own verses and the readings taken from it are not reproduced here.