What Was The Number Of Faces On Giovanni Dondi Dell'orologio's Astrarium?

Each of these required a separate, concentric pointer or "face" on the dial. Dondi considered each distinct moving index a vultus (face). So, a single dial for Mars might have:

Dondi’s treatise, Tractatus Astrarii , describes a brass, wheel-driven machine about 1 meter tall. It had seven distinct dial faces (one for each known planet and the Moon), plus a separate timekeeping dial. On these seven dials, there were (Latin: vultus or facies ). Each of these required a separate, concentric pointer