This is a famous picture by the artist Imperial Boy (帝国少年), who works in the anime industry. I sometimes claim that the entire genre of solarpunk is simply a riff on this picture.
If it’s not just “trees on buildings”, where does the Imperial Boy picture get its magic? Looking at it carefully and trying to analyze what I like about it, I think that much of it is about architecture, and even more of it is about the use of urban space — about how the structures in the picture shape the kinds of things you’d do if you were there. For example, here are five things I like:
The bipartisan deal contains a pot of money to repair America’s roads and bridges, and build a few more besides. This is the way we usually do infrastructure in America. First we build a ton of roads and bridges that are highly expensive to maintain, especially with our ruinously high construction costs (see this recent article by Jerusalem Demsas). Then, because costs are so high, we wait for a long time to repair the roads and bridges, until civil engineers start screeching, roads get potholed, and there’s a bridge collapse or two. Then we muster up the political will to throw the requisite shit-ton of money at the problem, the potholes and weak bridges get repaired for twice the amount it would have cost had we done it on a regular schedule and three times the amount it would cost if we were a normal rich country. And the whole cycle begins again.
Wang tiles (Hao Wang, 1961) are a class of formal systems. They are modelled visually by square tiles with a color on each side. A set of such tiles is selected, and copies of the tiles are arranged side by side with matching colors, without rotating or reflecting them.
The basic question about a set of Wang tiles is whether it can tile the plane or not, i.e., whether an entire infinite plane can be filled this way. The next question is whether this can be done in a periodic pattern.
In 1966, Wang's student Robert Berger solved the problem in the negative. He proved that no algorithm for the problem can exist, by showing how to translate any Turing machine into a set of Wang tiles that tiles the plane if and only if the Turing machine does not halt. The undecidability of the halting problem then implies the undecidability of Wang's tiling problem.