Hypothetical Bridges

Whipped these up on the train today. I had this idea for a spiral/ribbon bridge... then it turned into a helix bridge... then it turned into a sectional bridge based on undulating circular tunnels... then I got to my station and had to put the pen down. They aren't fully hashed out, but just some initial thoughts that could potentially be worked out later... or on my next train ride!

At the End of Mead Horn Bridge

Probably not the most buildable of structures, but that's never stopped me before.
I imagine the wind blowing through this would make some pretty crazy sounds.
There are a couple of wee silhouettes in place for scale...