The inside of the Real Chiesa di San Lorenzo's dome is lit by eight elliptical windows and crossed by a series of diagonal ribs tracing an eight-pointed star, at the center of which finds its place a regular octagon. Viewed from a perpendicular angle the dome blooms into an eight-petaled flower... but take just a few steps backwards and its lines will appear to twist into a series of demonic faces glaring down at the sinners below.