A film can have a geometry: lines, curves, circles, squares, angles, spirals.
It can also have an architecture: volumes, lights, shadows, contrasts, space, narrow corridors, spiral staircases.
Giornata nera per l'ariete (The Fifth Cord, AKA Black Day for Aries - Luigi Bazzoni, 1971) has spiral staircases everywhere. It's a movie made out of spiral staircases. If it did not strike you in the first place, take a second look at it. Almost every other scene has a spiral staircase in it.
In the background, in the foreground, in the frame of a window...
The spiral as the graphic backbone of the movie.
"The Fifth Cord" is also about astrology. Symbolism, zodiacal signs, fate, symmetry, the predictability of things. A kind of esoteric geometry, where the sign of Aries plays the core role:
take the horns of an aries - in their simplest shape, they are in fact spirals.
And if you look at a spiral staircase from above, it definitely looks like aries' horns.
It is always interesting, this obsession of a director for symbolism.
"Giornata nera per l'ariete" is an incredibly stylish film. Amateurs of design and architecture will definitely love it. Not to mention the great photography. Definitely a giallo bringing something to Giallo, by radicalising its aesthetics in every single detail - and with another of these amazing Morricone's scores.