Final answer:
The head of an Oba is made of cast bronze, depicting an idealized likeness of the Oba when he was young. The woven cap on the head is patterned after coral beads, with a single bead hanging down on the forehead as a tribute to the artist's skill.
Step-by-step explanation:
The head of an Oba is typically made of cast bronze. The bronze head is an idealized likeness of the Oba when he was young, with a woven cap patterned after coral beads. Coral beads were a valuable commodity imported for the Oba, and the cap has a single bead hanging down on the forehead as a tribute to the artist's skill.