Render out white wire geometry. Insert two copies of animation to video editor on different layers. Set both layers to additive blend mode. Apply purple multiply to bottom layer, turquoise multiply to top layer. Shift top layer ahead exactly 1 frame. Effect achieved.
I consider myself to be part of the “science side of Tumblr,” but I have now idea how that second picture was made by a spinning tree. Fast moving LEDs with a reasonably slow pulse-width modulation signal could do something similar, but not quite like this. It’s as if the tree was moved towards the camera very quickly, stopped for a fraction of a second, moved forward a few more inches very quickly, and stopped again, but that’s unlikely. Fellow scientists, theories?
look up light painting. The second photo was likely created by just moving the camera forward/backward, long exposure time will let you do that.