There are especially Venetian patterns, which, still, are quite universal. When we're in Venice, they remind us of home. When we're home, they remind us of Venice. It's generally completely subconscious. When we peel back our conscious mind, and peek inside, we find it's the physical phenomena that resonates with us.
Water has many ways to attack a semi-transparent surface. It splashes, with big enough drops to drip along the glass surface, leaving streaks. It mists, and this water occasionally collects into small vertical ponds. Streaks usually break-up into many different-sized droplets, which dry at various rates. If this goes on for a while, you end up with something like this:
Venice has many distinctive fabric and window patterns reminiscent of this. The bullseye windows above take their shape partly from the old process of making flat glass in circles, partly from echoes of symbolic art, and partly because the overall arrangement looks like water's foggy, drippy, alternating pattern against glass.
Like all good patterns, I found this one in the shower. Probably time to change the plastic curtain.
Now, something familiar to anyone who has spent too much time in the shower: you start to see shapes. Faces, often. You'll see more faces if there are mirrors or photos of faces, or actual faces, nearby. This is the "shape echo" effect, where our eye starts to search for similar shapes in the field of view. In the above sketch, I can eek out a gargoyle:
And then you see another Venetian art pattern -- making sculpture out of the dripping spaces in the shadows. And sometimes, these get dripped upon themselves.