Species of posthuman tree-snakes that evolved sapience again, using spirally coiled brains and a single hand at the end of their tails, a remnant of their ancestors feet.
The cities of the Snake People were tangles of pipe like tunnels, branching, three dimensional railroads and windowless, hole-like buildings. The cities were totally devoid of any plazas and open areas because of the species-wide agoraphobia of their inhabitants.

Their art includes books and vibrational ground-music.

They appear in the book "All tomorrows" by Nemo Ramjet