Description of how this image was created
When this month's TC-RTC theme was announced, I already had some partially-complete landscape-generating C++ code I wanted to continue playing with. At the same time, Sam Clough had expressed interested in having his short story "Systema Metropolis" illustrated. I contacted him and asked if he would build the machines in Wings3D if I would texture them and build the rest of the scene, and he agreed.
The grass texture is adapted from those provided by Geomorph, and the trees are produced by PovTree. The landscape geometry is generated by my own code, and the trees planted via my own macro.
I got lazy and didn't UV map the machine meshes; instead, I used a Povray slope texture on the shapes, which worked fairly well. Surfaces facing straight up have a mottled "metal photosynthesis" texture, surfaces that are vertical or facing down have a rust pattern, and faces that are diagonal but facing upward are shiny. The machine textures are all based on those that come with Povray.
All the shapes in this scene are meshes, except for a couple of Povray blob objects used to "shore up" the ground around some of the machines' feet.
Finally, I invite everyone to visit the Systema Metropolis page on DeviantArt, read the original story, and maybe contribute some illustrations of your own.
http://systemametropolis.deviantart.com/