The wednesday actually consists of two days for the Buddhists. The morning until noon is a first day and noon to midnight is considered a second day. And indeed, around the zedi there is one place to pray if you were born on a wednesday morning, in that case your planet is mercury and the animal the tusked elephant. Whereas if you were born on a wednesday afternoon, the animal is the tuskless elephant.
People come to pray at different places around the central zedi depending on which day of the week they were born. Each post corresponds to a different day and a different planet. For instance, people pray at the planetary post for saturn if they were born on a saturday and their animal sign is the naga or dragon serpent.